BACKGROUND Photoaging,a result of chronic sun exposure,leads to skin damage and pigmentation changes.Traditional treatments may have limitations in high-altitude areas like Yunnan Province.Intradermal Col Ⅰ injection...BACKGROUND Photoaging,a result of chronic sun exposure,leads to skin damage and pigmentation changes.Traditional treatments may have limitations in high-altitude areas like Yunnan Province.Intradermal Col Ⅰ injections stimulate collagen production,potentially improving skin quality.This study aims to assess the efficacy and safety of this treatment for photoaging.AIM To evaluate the efficacy and safety of intradermal typeΙcollagen(ColΙ)injection for treating photoaging.METHODS This prospective,self-controlled study investigated the impact of intradermal injections of ColΙon skin photodamage in 20 patients from the Yunnan Province.Total six treatment sessions were conducted every 4 wk±3 d.Before and after each treatment,facial skin characteristics were quantified using a VISIA skin detector.Skin thickness data were assessed using the ultrasound probes of the Dermalab skin detector.The Face-Q scale was used for subjective evaluation of the treatment effect by the patients.RESULTS The skin thickness of the right cheek consistently increased after each treatment session compared with baseline.The skin thickness of the left cheek significantly increased after the third through sixth treatment sessions compared with baseline.The skin thickness of the right zygomatic region increased after the second to sixth treatment sessions,whereas that of the left zygomatic region showed a significant increase after the fourth through sixth treatment sessions.The skin thickness of both temporal regions significantly increased after the fifth and sixth treatment sessions compared with baseline(P<0.05).These findings were also supported by skin ultrasound images.The feature count for the red areas and wrinkle feature count decreased following the treatment(P<0.05).VISIA assessments also revealed a decrease in the red areas after treatment.The Face-QSatisfaction with Facial Appearance Overall and Face-Q-Satisfaction with Skin scores significantly increased after each treatment session.The overall appearance of the patients improved after treatment.CONCLUSION Intradermal ColΙinjection improves photoaging,with higher patient satisfaction and fewer adverse reactions,and could be an effective treatment method for populations residing in high-altitude areas.展开更多
In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such events.These pulsed X-rays can be captured using a satellite-borne X-ray detect...In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such events.These pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric transmission.To quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction.The proposed method is an improvement over the traditional analytical method that only computes direct-transmission X-rays.The traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo method.Our improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain scenarios.Moreover,its computation time is 48,000 times faster than that of the Monte Carlo method.These results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects.展开更多
Since China’s reform and opening-up,the growing disparity between urban and rural areas and regions has led to massive migration.With China’s Rural Revitalization Strategy and the industrial transfer from the easter...Since China’s reform and opening-up,the growing disparity between urban and rural areas and regions has led to massive migration.With China’s Rural Revitalization Strategy and the industrial transfer from the eastern coastal areas to the inland,the migration direction and pattern of the floating population have undergone certain changes.Using the 2017 China Migrants Dynamic Survey(CMDS),excluding Hong Kong,Macao,and Taiwan regions of China,organized by China’s National Health Commission,the relationship matrix of the floating population is constructed according to the inflow place of the interviewees and their outflow place(the location of the registered residence)in the questionnaire survey.We then apply the complex network model to analyze the migration direction and network pattern of China’s floating population from the city scale.The migration network shows an obvious hierarchical agglomeration.The first-,second-,third-and fourth-tier distribution cities are municipalities directly under the central government,provincial capital cities,major cities in the central and western regions and ordinary cities in all provinces,respectively.The migration trend is from the central and western regions to the eastern coastal areas.The migration network has‘small world’characteristics,forming nine communities.It shows that most node cities in the same community are closely linked and geographically close,indicating that the migration network of floating population is still affected by geographical proximity.Narrowing the urban-rural and regional differences will promote the rational distribution this population.It is necessary to strengthen the reform of the registered residence system,so that the floating population can enjoy urban public services comparable to other populations,and allow migrants to live and work in peace.展开更多
The Submerged Floating Tunnel(SFT)relies on a tensioned mooring system for precise positioning.The sudden breakage of a single cable can trigger an immediate alteration in the constraint conditions of the tube,inducin...The Submerged Floating Tunnel(SFT)relies on a tensioned mooring system for precise positioning.The sudden breakage of a single cable can trigger an immediate alteration in the constraint conditions of the tube,inducing a transient heave response within the structure along with a transient increase in cable tension experienced by adjacent cables.In more severe cases,this may even lead to a progressive failure culminating in the global destruction of the SFT.This study used ANSYS/AQWA to establish a numerical model of the entire length SFT for the hydrodynamic response analysis,and conducted a coupled calculation of the dynamic responses of the SFT-mooring line model based on Orca Flex to study the global dynamic responses of the SFT at the moment of cable breakage and the redistribution of cable internal forces.The most unfavorable position for SFT cable breakage was identified,the influence mechanism of cable breakage at different positions on the global dynamic response was revealed,and the progressive chain failure pattern caused by localized cable breakage are also clarified.展开更多
A numerical study of linear wave scattering over a floating platform has been simulated by an efficient numericalmodel in this letter.The non-hydrostatic model is used to simulate the free surface and the uneven botto...A numerical study of linear wave scattering over a floating platform has been simulated by an efficient numericalmodel in this letter.The non-hydrostatic model is used to simulate the free surface and the uneven bottom.For thesolid body modelling,the immersed boundary method(IBM)is implemented by introducing a virtual boundaryforce into the momentum equations to emulate the boundary conditions.This implementation enhances theability of the model to simulate interactions between waves and floating structures.A numerical case involvingwave interactions with a floating platform is studied to validate the numerical model.By simulating the wavepropagation,the numerical model captures the variation of the wave scattering very well,which verifies theperformance of the numerical model and the robust strategy of the IBM.展开更多
Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring forces.Designing a reasonable gap between...Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring forces.Designing a reasonable gap between the flume wall and the FBs is a critical step in 2D flume tests.However,research on the effect of the gap on the accuracy of 2D FB experimental results is scarce.To address this issue,a numerical wave tank is developed using CFD to estimate the wave-FB interaction of a moored dual-cylindrical FB,and the results are compared to experimental data from a previously published work.There is good agreement between them,indicating that the numerical model is sufficiently accurate.The numerical model is then applied to explore the effect of gap diffraction on the performance of FBs in2D experiments.It was discovered that the nondimensional gap length L_(Gap)/W_(Pool)should be smaller than 7.5%to ensure that the relative error of the transmission coefficient is smaller than 3%.The influence of the gap is also related to the entering wave properties,such as the wave height and period.展开更多
The scattering of normally incident water waves by two surface-piercing inclined perforated barriers in water with a uniform finite depth is investigated within the framework of linear water wave theory.Considering th...The scattering of normally incident water waves by two surface-piercing inclined perforated barriers in water with a uniform finite depth is investigated within the framework of linear water wave theory.Considering that thin barriers are zero-thickness,a novel numerical method involving the the coupling of the dual boundary element method(DBEM)with damping layers is applied.In order to effectively damp out the reflected waves,two damping layers,instead of pseudoboundaries are implemented near the two side boundaries of the computational domain.Thus,the modified linearized free surface boundary conditions are formulated and used for solving both the ordinary boundary integral equation as well as the hypersingular boundary integral equation for degenerate boundaries.The newly developed numerical method is validated against analytical methods using the matched eigenfunction expansion method for the special case of two vertical barriers or the inclined angle to the vertical being zero.The influence of the length of the two damping layers has been discussed.Moreover,these findings are also validated against previous results for several cases.After validation,the numerical results for the reflection coefficient,transmission coefficient and dissipation coefficient are obtained by varying the inclination angle and porosity-effect parameter.The effects of both the inclination angle and the porosity on the amplitudes of wave forces acting on both the front and rear barriers are also investigated.It is found that the effect of the inclination angle mainly shifts the location of the extremal values of the reflection and the transmission coefficients.Additionally,a moderate value of the porosity-parameter is quite effective at dissipating wave energy and mitigating the wave loads on dual barriers.展开更多
Recently,semisubmersible floating offshore wind turbine technologies have received considerable attention.For the coupled simulation of semisubmersible floating offshore wind energy,the platform is usually considered ...Recently,semisubmersible floating offshore wind turbine technologies have received considerable attention.For the coupled simulation of semisubmersible floating offshore wind energy,the platform is usually considered a rigid model,which could affect the calculation accuracy of the dynamic responses.The dynamic responses of a TripleSpar floating offshore wind turbine equipped with a 10 MW offshore wind turbine are discussed herein.The simulation of a floating offshore wind turbine under regular waves,white noise waves,and combined wind-wave conditions is conducted.The effects of the tower and platform flexibility on the motion and force responses of the TripleSpar semisubmersible floating offshore wind turbine are investigated.The results show that the flexibility of the tower and platform can influence the dynamic responses of a TripleSpar semisubmersible floating offshore wind turbine.Considering the flexibility of the tower and platform,the tower and platform pitch motions markedly increased compared with the fully rigid model.Moreover,the force responses,particularly for tower base loads,are considerably influenced by the flexibility of the tower and platform.Thus,the flexibility of the tower and platform for the coupled simulation of floating offshore wind turbines must be appropriately examined.展开更多
The selection of wave force models will significantly impact the structural responses of floating wind turbines.In this study,comparisons of wave force model effects on the structural responses and fatigue loads of a ...The selection of wave force models will significantly impact the structural responses of floating wind turbines.In this study,comparisons of wave force model effects on the structural responses and fatigue loads of a semi-submersible floating wind turbine(SFWT)were conducted.Simulations were performed by employing the Morison equation(ME)with linear or second-order wave kinematics and potential flow theory(PFT)with first-or second-order wave forces.A comparison of regular waves,irregular waves,and coupled wind/waves analyses with the experimental data showed that many of the simulation results and experimental data are relatively consistent.However,notable discrepancies are found in the response amplitude operators for platform heave,tower base bending moment,and tension in mooring lines.PFT models give more satisfactory results of heave but more significant discrepan-cies in tower base bending moment than the ME models.In irregular wave analyses,low-frequency resonances were captured by PFT models with second-order difference-frequency terms,and high-frequency resonances were captured by the ME models or PFT models with second-order sum-frequency terms.These force models capture the response frequencies but do not reasonably predict the response amplitudes.The coupled wind/waves analyses showed more satisfactory results than the wave-only analyses.However,an important detail to note is that this satisfactory result is based on the overprediction of wind-induced responses.展开更多
This paper examined the relationship between cultural consumption and the floating population’s integration into host cities based on data from China’s Seventh National Population Census and the 2018 China Migrants ...This paper examined the relationship between cultural consumption and the floating population’s integration into host cities based on data from China’s Seventh National Population Census and the 2018 China Migrants Dynamic Survey(CMDS).The findings indicate that improving the floating population’s consumption level and quality,especially the quality of development-oriented cultural consumption,can significantly improve the level of their integration.Moreover,development-oriented cultural consumption has a positive effect on the floating population’s integration and social participation,while entertainment-oriented cultural consumption facilitates their integration mainly by improving their sense of well-being.These findings could guide policymakers in developing targeted cultural consumption policies,implementing specific regional industry adjustments,and expanding domestic consumption demand.展开更多
[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the flo...[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the floating balls. [Methods] The effects of the types and amounts of isocyanate, chain extenders and polyether polyols on the gelation rate, adhesion and wear resistance of polyurea elastomer were investigated, and it was finally determined the preparation process of polyurea elastomer using liquid isophorone diisocyanate (IPDI) and amino-terminated polyether (D2000) as the main raw materials, dimethylthiotoluene diamine (E300) as the chain extender and silica as the wear resistance modifier through two-step solution polymerization of prepolymerization and chain extension. [Results] The physical properties and chemical resistance tests of spray polyurea elastomer showed that it had good physical properties and acid and alkali resistance, and could meet the requirements of spraying and protection of EPS floating ball surface in marine environment. [Conclusions] Polyurea elastomer coating can improve the aging resistance, wear resistance and acid and alkali resistance of EPS floating balls, and prevent them from being fragile and floating randomly to form marine floating garbage which results in "white pollution".展开更多
Objective:To evaluate the efficacy of combination perindopril/amlodipine tablets in patients with high-altitude hypertension who were previously unable to control their blood pressure with monotherapy.Methods:A total ...Objective:To evaluate the efficacy of combination perindopril/amlodipine tablets in patients with high-altitude hypertension who were previously unable to control their blood pressure with monotherapy.Methods:A total of 151 patients with high-altitude hypertension whose blood pressure remained inadequately controlled with previous monotherapy were enrolled in this study.All patients received an 8-week treatment with a combination of perindopril/amlodipine tablets,consisting of perindopril 10 mg/day and amlodipine 5 mg/day.Blood pressure measurements,including both diastolic and systolic pressures,were taken at baseline,and after 2,4,6,and 8 weeks of treatment.Results:After 8 weeks of treatment,there was a significant reduction in both average systolic and diastolic blood pressure compared to baseline(P<0.0001).Specifically,the average systolic blood pressure decreased by 24.45±13.75 mmHg,and the average diastolic blood pressure decreased by 13.37±8.40 mmHg.The overall heart rate showed no significant changes during the treatment period.Conclusion:A combination of perindopril/amlodipine tablets significantly improved blood pressure control in patients with high-altitude hypertension after 8 weeks of treatment.These results support the efficacy of combination perindopril/amlodipine as a viable treatment option for high-altitude hypertension.展开更多
Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rock...Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas.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
In this study,the frequency characteristics of the turbulent wind and the effects of wind-wave coupling on the low-and high-frequency responses of semi-submersible floating offshore wind turbines(FOWT)are investigated...In this study,the frequency characteristics of the turbulent wind and the effects of wind-wave coupling on the low-and high-frequency responses of semi-submersible floating offshore wind turbines(FOWT)are investigated.Various wave load components,such as first-order wave loads,combined first-and second-order difference-frequency wave loads,combined first-and second-order sum-frequency wave loads,and first-and complete second-order wave loads are taken into consideration,while different turbulent environments are considered in aerodynamic loads.The com-parison is based on time histories and frequency spectra of platform motions and structural load responses and statistical values.The findings indicate that the second-order difference-frequency wave loads will significantly increase the natural frequency of low-frequency motion in the responses of the platform motion and structure load of the semi-submersible platform,which will cause structural fatigue damage.Under the action of turbulent wind,the influences of second-order wave loads on the platform motion and structural load response cannot be ignored,especially under extreme sea conditions.Therefore,in order to evaluate the dynamic responses of semi-submersible FOWT more accurately,the actual environment should be simulated more realistically.展开更多
The rapid growth of the demand for carbon nanotubes(CNTs) has greatly promoted their large-scale synthesis and development. However,the continuous production of CNT fibers by floating catalyst chemical vapor depositio...The rapid growth of the demand for carbon nanotubes(CNTs) has greatly promoted their large-scale synthesis and development. However,the continuous production of CNT fibers by floating catalyst chemical vapor deposition(FCCVD) requires a large amount of non-renewable carbon sources. Here, the continuous production of highly graphitized CNT yarns from biomass tannic acid(TA) is reported. The chelation of TA and catalyst promotes the rapid cracking of biomass into carbon source gas, and the pyrolysis cracking produces the reducing gas, which solves the problems of the continuous production of CNT yarns using biomass. Through simple twisting, the mechanical strength of CNT yarn can reach 886 ± 46 MPa, and the electrical conductivity and graphitization(IG/ID) can reach 2 × 10^(5)S m^(-1)and 6.3, respectively. This work presents a promising solution for the continuous preparation of CNT yarns based on green raw material.展开更多
The dynamic responses of a floating vertical axis wind turbine(VAWT)are assessed on the basis of an aero-hydro-mooring coupled model.The aerodynamic loads on the rotor are acquired with double-multiple stream tube met...The dynamic responses of a floating vertical axis wind turbine(VAWT)are assessed on the basis of an aero-hydro-mooring coupled model.The aerodynamic loads on the rotor are acquired with double-multiple stream tube method.First-and second-order wave loads are calculated on the basis of 3D potential theory.The mooring loads are simulated by catenary theory.The coupled model is established,and a numerical code is programmed to investigate the dynamic response of the semi-submersible VAWT.A model test is then conducted,and the numerical code is validated considering the hydrodynamic performance of the floating buoy.The responses of the floating VAWT are studied through the numerical simulation under the sea states of wind and regular/irregular waves.The effects of the second-order wave force on the motions are also investigated.Results show that the slow-drift responses in surge and pitch motions are significantly excited by the second-order wave forces.Furthermore,the effect of foundation motion on aerodynamic loads is examined.The normal and tangential forces of the blades demonstrate a slight increase due to the coupling effect between the buoy motion and the aerodynamic loads.展开更多
To reduce the vibration and sound radiation of underwater cylindrical shells,a skin composed of micro floating raft arrays and a compliant wall is proposed in this paper.A vibroacoustic coupling model of a finite cyli...To reduce the vibration and sound radiation of underwater cylindrical shells,a skin composed of micro floating raft arrays and a compliant wall is proposed in this paper.A vibroacoustic coupling model of a finite cylindrical shell covered with this skin for the case of turbulence excitation is established based on the shell theories of Donnell.The model is solved with the modal superposition method to investigate the effects of the structural parameters of micro floating raft elements on the performance of reducing vibration and sound radiation of the cylindrical shell of this skin.The results indicate that increasing the stiffness ratio,damping ratio,mass ratio,or decreasing the interval betweenmicro floating raft elements can improve the vibration and sound radiation reduction performance of this skin over the frequency range 0∼2000 Hz.Moreover,the mean quadratic velocity level and sound radiation power level of the finite cylindrical shell with this skin can be reduced by 12.00 dB and 9.65 dB respectively compared to the finite cylindrical shell with homogeneous viscoelastic coating in the frequency range from0∼2000Hz,implying a favorable performance of this skin for reducing the vibration and sound radiation of cylindrical shells.展开更多
Submerged floating tunnel(SFTs)are typically subjected to complex external environmental and internal loads such as wave currents and traffic load.In this study,this problem is investigated through a finite element me...Submerged floating tunnel(SFTs)are typically subjected to complex external environmental and internal loads such as wave currents and traffic load.In this study,this problem is investigated through a finite element method able to account for fluid-structure interaction.The obtained results show that increasing the number of vehicles per unit length enhances the transverse vibrational displacements of the SFT cross sections.Under ultimate traffic load condition,one-way and two-way syntropic distributions can promote the dynamic responses of SFTs whereas two-way reverse distributions have the opposite effect.展开更多
Recently,β-Ga_(2)O_(3),an ultra-wide bandgap semiconductor,has shown great potential to be used in power devices blessed with its unique material properties.For instance,the measured average critical field of the ver...Recently,β-Ga_(2)O_(3),an ultra-wide bandgap semiconductor,has shown great potential to be used in power devices blessed with its unique material properties.For instance,the measured average critical field of the vertical Schottky barrier diode(SBD)based onβ-Ga_(2)O_(3) has reached 5.45 MV/cm,and no device in any material has measured a greater before.However,the high electric field of theβ-Ga_(2)O_(3) SBD makes it challenging to manage the electric field distribution and leakage current.Here,we showβ-Ga_(2)O_(3) junction barrier Schottky diode with NiO p-well floating field rings(FFRs).For the central anode,we filled a circular trench array with NiO to reduce the surface field under the Schottky contact between them to reduce the leakage current of the device.For the anode edge,experimental results have demonstrated that the produced NiO/β-Ga_(2)O_(3) heterojunction FFRs enable the spreading of the depletion region,thereby mitigating the crowding effect of electric fields at the anode edge.Additionally,simulation results indicated that the p-NiO field plate structure designed at the edges of the rings and central anode can further reduce the electric field.This work verified the feasibility of the heterojunction FFRs inβ-Ga_(2)O_(3) devices based on the experimental findings and provided ideas for managing the electric field ofβ-Ga_(2)O_(3) SBD.展开更多
文摘BACKGROUND Photoaging,a result of chronic sun exposure,leads to skin damage and pigmentation changes.Traditional treatments may have limitations in high-altitude areas like Yunnan Province.Intradermal Col Ⅰ injections stimulate collagen production,potentially improving skin quality.This study aims to assess the efficacy and safety of this treatment for photoaging.AIM To evaluate the efficacy and safety of intradermal typeΙcollagen(ColΙ)injection for treating photoaging.METHODS This prospective,self-controlled study investigated the impact of intradermal injections of ColΙon skin photodamage in 20 patients from the Yunnan Province.Total six treatment sessions were conducted every 4 wk±3 d.Before and after each treatment,facial skin characteristics were quantified using a VISIA skin detector.Skin thickness data were assessed using the ultrasound probes of the Dermalab skin detector.The Face-Q scale was used for subjective evaluation of the treatment effect by the patients.RESULTS The skin thickness of the right cheek consistently increased after each treatment session compared with baseline.The skin thickness of the left cheek significantly increased after the third through sixth treatment sessions compared with baseline.The skin thickness of the right zygomatic region increased after the second to sixth treatment sessions,whereas that of the left zygomatic region showed a significant increase after the fourth through sixth treatment sessions.The skin thickness of both temporal regions significantly increased after the fifth and sixth treatment sessions compared with baseline(P<0.05).These findings were also supported by skin ultrasound images.The feature count for the red areas and wrinkle feature count decreased following the treatment(P<0.05).VISIA assessments also revealed a decrease in the red areas after treatment.The Face-QSatisfaction with Facial Appearance Overall and Face-Q-Satisfaction with Skin scores significantly increased after each treatment session.The overall appearance of the patients improved after treatment.CONCLUSION Intradermal ColΙinjection improves photoaging,with higher patient satisfaction and fewer adverse reactions,and could be an effective treatment method for populations residing in high-altitude areas.
文摘In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such events.These pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric transmission.To quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction.The proposed method is an improvement over the traditional analytical method that only computes direct-transmission X-rays.The traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo method.Our improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain scenarios.Moreover,its computation time is 48,000 times faster than that of the Monte Carlo method.These results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects.
基金Under the auspices of the Fund of Social Sciences Research,Ministry of Education of China(No.17YJA840011)。
文摘Since China’s reform and opening-up,the growing disparity between urban and rural areas and regions has led to massive migration.With China’s Rural Revitalization Strategy and the industrial transfer from the eastern coastal areas to the inland,the migration direction and pattern of the floating population have undergone certain changes.Using the 2017 China Migrants Dynamic Survey(CMDS),excluding Hong Kong,Macao,and Taiwan regions of China,organized by China’s National Health Commission,the relationship matrix of the floating population is constructed according to the inflow place of the interviewees and their outflow place(the location of the registered residence)in the questionnaire survey.We then apply the complex network model to analyze the migration direction and network pattern of China’s floating population from the city scale.The migration network shows an obvious hierarchical agglomeration.The first-,second-,third-and fourth-tier distribution cities are municipalities directly under the central government,provincial capital cities,major cities in the central and western regions and ordinary cities in all provinces,respectively.The migration trend is from the central and western regions to the eastern coastal areas.The migration network has‘small world’characteristics,forming nine communities.It shows that most node cities in the same community are closely linked and geographically close,indicating that the migration network of floating population is still affected by geographical proximity.Narrowing the urban-rural and regional differences will promote the rational distribution this population.It is necessary to strengthen the reform of the registered residence system,so that the floating population can enjoy urban public services comparable to other populations,and allow migrants to live and work in peace.
基金financially supported by the National Key Research and Development Program of China(Grant No.2022YFB2602800)Science and Technology Projects of Liaoning Province(Grant No.2023011352-JH1/110)。
文摘The Submerged Floating Tunnel(SFT)relies on a tensioned mooring system for precise positioning.The sudden breakage of a single cable can trigger an immediate alteration in the constraint conditions of the tube,inducing a transient heave response within the structure along with a transient increase in cable tension experienced by adjacent cables.In more severe cases,this may even lead to a progressive failure culminating in the global destruction of the SFT.This study used ANSYS/AQWA to establish a numerical model of the entire length SFT for the hydrodynamic response analysis,and conducted a coupled calculation of the dynamic responses of the SFT-mooring line model based on Orca Flex to study the global dynamic responses of the SFT at the moment of cable breakage and the redistribution of cable internal forces.The most unfavorable position for SFT cable breakage was identified,the influence mechanism of cable breakage at different positions on the global dynamic response was revealed,and the progressive chain failure pattern caused by localized cable breakage are also clarified.
基金supported by Shanghai 2021“Science and Technology Innovation Action Plan”:Scientific and Technological Projects for Social Development(Grant No.21DZ1202701).
文摘A numerical study of linear wave scattering over a floating platform has been simulated by an efficient numericalmodel in this letter.The non-hydrostatic model is used to simulate the free surface and the uneven bottom.For thesolid body modelling,the immersed boundary method(IBM)is implemented by introducing a virtual boundaryforce into the momentum equations to emulate the boundary conditions.This implementation enhances theability of the model to simulate interactions between waves and floating structures.A numerical case involvingwave interactions with a floating platform is studied to validate the numerical model.By simulating the wavepropagation,the numerical model captures the variation of the wave scattering very well,which verifies theperformance of the numerical model and the robust strategy of the IBM.
基金financially supported by China National Funds for Distinguished Young Scientists(Grant No.52025112)the Key Projects of the National Natural Science Foundation of China(Grant No.52331011)。
文摘Two-dimensional(2D)flume experiments are useful in investigating the performances of floating breakwaters(FBs),including hydrodynamic performances,motion responses,and mooring forces.Designing a reasonable gap between the flume wall and the FBs is a critical step in 2D flume tests.However,research on the effect of the gap on the accuracy of 2D FB experimental results is scarce.To address this issue,a numerical wave tank is developed using CFD to estimate the wave-FB interaction of a moored dual-cylindrical FB,and the results are compared to experimental data from a previously published work.There is good agreement between them,indicating that the numerical model is sufficiently accurate.The numerical model is then applied to explore the effect of gap diffraction on the performance of FBs in2D experiments.It was discovered that the nondimensional gap length L_(Gap)/W_(Pool)should be smaller than 7.5%to ensure that the relative error of the transmission coefficient is smaller than 3%.The influence of the gap is also related to the entering wave properties,such as the wave height and period.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51809209 and 11702244)the Open Fund of Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province(Grant No.2021SS04).
文摘The scattering of normally incident water waves by two surface-piercing inclined perforated barriers in water with a uniform finite depth is investigated within the framework of linear water wave theory.Considering that thin barriers are zero-thickness,a novel numerical method involving the the coupling of the dual boundary element method(DBEM)with damping layers is applied.In order to effectively damp out the reflected waves,two damping layers,instead of pseudoboundaries are implemented near the two side boundaries of the computational domain.Thus,the modified linearized free surface boundary conditions are formulated and used for solving both the ordinary boundary integral equation as well as the hypersingular boundary integral equation for degenerate boundaries.The newly developed numerical method is validated against analytical methods using the matched eigenfunction expansion method for the special case of two vertical barriers or the inclined angle to the vertical being zero.The influence of the length of the two damping layers has been discussed.Moreover,these findings are also validated against previous results for several cases.After validation,the numerical results for the reflection coefficient,transmission coefficient and dissipation coefficient are obtained by varying the inclination angle and porosity-effect parameter.The effects of both the inclination angle and the porosity on the amplitudes of wave forces acting on both the front and rear barriers are also investigated.It is found that the effect of the inclination angle mainly shifts the location of the extremal values of the reflection and the transmission coefficients.Additionally,a moderate value of the porosity-parameter is quite effective at dissipating wave energy and mitigating the wave loads on dual barriers.
基金funded by the Key Technology Research and Development Program(Nos.2022YFB4201301,and 2022YFB4201304)the National Natural Science Foundation of China(Nos.52101333,52071058,51939002,and 52071301)+2 种基金the Zhejiang Provincial Natural Science Foundation of China(No.LQ21E090009)supported by the Natural Science Foundation of Liaoning Province(No.2022-KF-18-01)the special funds for Promoting High-Quality Development from the Department of Natural Resources of Guangdong Province(No.GDNRC[2020]016).
文摘Recently,semisubmersible floating offshore wind turbine technologies have received considerable attention.For the coupled simulation of semisubmersible floating offshore wind energy,the platform is usually considered a rigid model,which could affect the calculation accuracy of the dynamic responses.The dynamic responses of a TripleSpar floating offshore wind turbine equipped with a 10 MW offshore wind turbine are discussed herein.The simulation of a floating offshore wind turbine under regular waves,white noise waves,and combined wind-wave conditions is conducted.The effects of the tower and platform flexibility on the motion and force responses of the TripleSpar semisubmersible floating offshore wind turbine are investigated.The results show that the flexibility of the tower and platform can influence the dynamic responses of a TripleSpar semisubmersible floating offshore wind turbine.Considering the flexibility of the tower and platform,the tower and platform pitch motions markedly increased compared with the fully rigid model.Moreover,the force responses,particularly for tower base loads,are considerably influenced by the flexibility of the tower and platform.Thus,the flexibility of the tower and platform for the coupled simulation of floating offshore wind turbines must be appropriately examined.
基金funded by the National Natural Science Foundation of China(No.51809135)the Shandong Provincial Natural Science Foundation(No.ZR2018BEE 047)+1 种基金the National Natural Science Foundation of China–Shandong Joint Fund(No.U2006229)the SKL of HESS(No.HESS-1808).
文摘The selection of wave force models will significantly impact the structural responses of floating wind turbines.In this study,comparisons of wave force model effects on the structural responses and fatigue loads of a semi-submersible floating wind turbine(SFWT)were conducted.Simulations were performed by employing the Morison equation(ME)with linear or second-order wave kinematics and potential flow theory(PFT)with first-or second-order wave forces.A comparison of regular waves,irregular waves,and coupled wind/waves analyses with the experimental data showed that many of the simulation results and experimental data are relatively consistent.However,notable discrepancies are found in the response amplitude operators for platform heave,tower base bending moment,and tension in mooring lines.PFT models give more satisfactory results of heave but more significant discrepan-cies in tower base bending moment than the ME models.In irregular wave analyses,low-frequency resonances were captured by PFT models with second-order difference-frequency terms,and high-frequency resonances were captured by the ME models or PFT models with second-order sum-frequency terms.These force models capture the response frequencies but do not reasonably predict the response amplitudes.The coupled wind/waves analyses showed more satisfactory results than the wave-only analyses.However,an important detail to note is that this satisfactory result is based on the overprediction of wind-induced responses.
基金Study on Green Development in Agriculture and Rural Areas to Enable the Building of a Low-Carbon Society (LD23YB02)funded by the 2023 Chengdu Green and Low-Carbon Development Research Base Project.
文摘This paper examined the relationship between cultural consumption and the floating population’s integration into host cities based on data from China’s Seventh National Population Census and the 2018 China Migrants Dynamic Survey(CMDS).The findings indicate that improving the floating population’s consumption level and quality,especially the quality of development-oriented cultural consumption,can significantly improve the level of their integration.Moreover,development-oriented cultural consumption has a positive effect on the floating population’s integration and social participation,while entertainment-oriented cultural consumption facilitates their integration mainly by improving their sense of well-being.These findings could guide policymakers in developing targeted cultural consumption policies,implementing specific regional industry adjustments,and expanding domestic consumption demand.
基金Supported by Special Project for High-quality Development of Marine Services and Fishery in Fujian Province in 2023(FJHY-YYKJ-2023-1-3)。
文摘[Objectives] This study was conducted to develop a polyurea elastomer which can be sprayed on the surface of expanded polystyrene (EPS) floating balls, so as to improve the surface strength and service life of the floating balls. [Methods] The effects of the types and amounts of isocyanate, chain extenders and polyether polyols on the gelation rate, adhesion and wear resistance of polyurea elastomer were investigated, and it was finally determined the preparation process of polyurea elastomer using liquid isophorone diisocyanate (IPDI) and amino-terminated polyether (D2000) as the main raw materials, dimethylthiotoluene diamine (E300) as the chain extender and silica as the wear resistance modifier through two-step solution polymerization of prepolymerization and chain extension. [Results] The physical properties and chemical resistance tests of spray polyurea elastomer showed that it had good physical properties and acid and alkali resistance, and could meet the requirements of spraying and protection of EPS floating ball surface in marine environment. [Conclusions] Polyurea elastomer coating can improve the aging resistance, wear resistance and acid and alkali resistance of EPS floating balls, and prevent them from being fragile and floating randomly to form marine floating garbage which results in "white pollution".
文摘Objective:To evaluate the efficacy of combination perindopril/amlodipine tablets in patients with high-altitude hypertension who were previously unable to control their blood pressure with monotherapy.Methods:A total of 151 patients with high-altitude hypertension whose blood pressure remained inadequately controlled with previous monotherapy were enrolled in this study.All patients received an 8-week treatment with a combination of perindopril/amlodipine tablets,consisting of perindopril 10 mg/day and amlodipine 5 mg/day.Blood pressure measurements,including both diastolic and systolic pressures,were taken at baseline,and after 2,4,6,and 8 weeks of treatment.Results:After 8 weeks of treatment,there was a significant reduction in both average systolic and diastolic blood pressure compared to baseline(P<0.0001).Specifically,the average systolic blood pressure decreased by 24.45±13.75 mmHg,and the average diastolic blood pressure decreased by 13.37±8.40 mmHg.The overall heart rate showed no significant changes during the treatment period.Conclusion:A combination of perindopril/amlodipine tablets significantly improved blood pressure control in patients with high-altitude hypertension after 8 weeks of treatment.These results support the efficacy of combination perindopril/amlodipine as a viable treatment option for high-altitude hypertension.
基金This work was financially supported by National Natural Science Foundation of China(Grant Nos.U2244226,U2244227 and 42177172).
文摘Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas.
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supported by the Natural Science Foundation of Zhejiang Province(Grant No.LHZ21E090003)the National Nature Science Foundation of China(Grant No.52171279)+1 种基金Zhoushan Science&Technology Project(Grant No.2021C21002)supported by CNPq(Conselho Nacional de Desenvolvimento Científico e Tecnológico,Grant No.301474/2017-6).
文摘In this study,the frequency characteristics of the turbulent wind and the effects of wind-wave coupling on the low-and high-frequency responses of semi-submersible floating offshore wind turbines(FOWT)are investigated.Various wave load components,such as first-order wave loads,combined first-and second-order difference-frequency wave loads,combined first-and second-order sum-frequency wave loads,and first-and complete second-order wave loads are taken into consideration,while different turbulent environments are considered in aerodynamic loads.The com-parison is based on time histories and frequency spectra of platform motions and structural load responses and statistical values.The findings indicate that the second-order difference-frequency wave loads will significantly increase the natural frequency of low-frequency motion in the responses of the platform motion and structure load of the semi-submersible platform,which will cause structural fatigue damage.Under the action of turbulent wind,the influences of second-order wave loads on the platform motion and structural load response cannot be ignored,especially under extreme sea conditions.Therefore,in order to evaluate the dynamic responses of semi-submersible FOWT more accurately,the actual environment should be simulated more realistically.
基金the support from the Science and Technology Commission of Shanghai Municipality (20JC1414900)the Joint Funds of the National Natural Science Foundation of China (U20A20257)+1 种基金the Program of Shanghai Academic/Technology Research Leader (20XD1433700)the International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality (20520740800)。
文摘The rapid growth of the demand for carbon nanotubes(CNTs) has greatly promoted their large-scale synthesis and development. However,the continuous production of CNT fibers by floating catalyst chemical vapor deposition(FCCVD) requires a large amount of non-renewable carbon sources. Here, the continuous production of highly graphitized CNT yarns from biomass tannic acid(TA) is reported. The chelation of TA and catalyst promotes the rapid cracking of biomass into carbon source gas, and the pyrolysis cracking produces the reducing gas, which solves the problems of the continuous production of CNT yarns using biomass. Through simple twisting, the mechanical strength of CNT yarn can reach 886 ± 46 MPa, and the electrical conductivity and graphitization(IG/ID) can reach 2 × 10^(5)S m^(-1)and 6.3, respectively. This work presents a promising solution for the continuous preparation of CNT yarns based on green raw material.
基金The study is supported by the National Natural Science Foundation of China(No.51879190)the Tianjin Research Innovation Project for Postgraduate Students(No.2021YJSB185).
文摘The dynamic responses of a floating vertical axis wind turbine(VAWT)are assessed on the basis of an aero-hydro-mooring coupled model.The aerodynamic loads on the rotor are acquired with double-multiple stream tube method.First-and second-order wave loads are calculated on the basis of 3D potential theory.The mooring loads are simulated by catenary theory.The coupled model is established,and a numerical code is programmed to investigate the dynamic response of the semi-submersible VAWT.A model test is then conducted,and the numerical code is validated considering the hydrodynamic performance of the floating buoy.The responses of the floating VAWT are studied through the numerical simulation under the sea states of wind and regular/irregular waves.The effects of the second-order wave force on the motions are also investigated.Results show that the slow-drift responses in surge and pitch motions are significantly excited by the second-order wave forces.Furthermore,the effect of foundation motion on aerodynamic loads is examined.The normal and tangential forces of the blades demonstrate a slight increase due to the coupling effect between the buoy motion and the aerodynamic loads.
基金supported by the National Natural Science Foundation of China(Grant Nos.51775123,52075111)the Fundamental Research Funds for the Central Universities(Grant No.3072021CF0702).
文摘To reduce the vibration and sound radiation of underwater cylindrical shells,a skin composed of micro floating raft arrays and a compliant wall is proposed in this paper.A vibroacoustic coupling model of a finite cylindrical shell covered with this skin for the case of turbulence excitation is established based on the shell theories of Donnell.The model is solved with the modal superposition method to investigate the effects of the structural parameters of micro floating raft elements on the performance of reducing vibration and sound radiation of the cylindrical shell of this skin.The results indicate that increasing the stiffness ratio,damping ratio,mass ratio,or decreasing the interval betweenmicro floating raft elements can improve the vibration and sound radiation reduction performance of this skin over the frequency range 0∼2000 Hz.Moreover,the mean quadratic velocity level and sound radiation power level of the finite cylindrical shell with this skin can be reduced by 12.00 dB and 9.65 dB respectively compared to the finite cylindrical shell with homogeneous viscoelastic coating in the frequency range from0∼2000Hz,implying a favorable performance of this skin for reducing the vibration and sound radiation of cylindrical shells.
基金supported by Chongqing Natural Science Foundation(Grant No.cstc2020jcyj-msxmX0923).
文摘Submerged floating tunnel(SFTs)are typically subjected to complex external environmental and internal loads such as wave currents and traffic load.In this study,this problem is investigated through a finite element method able to account for fluid-structure interaction.The obtained results show that increasing the number of vehicles per unit length enhances the transverse vibrational displacements of the SFT cross sections.Under ultimate traffic load condition,one-way and two-way syntropic distributions can promote the dynamic responses of SFTs whereas two-way reverse distributions have the opposite effect.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61925110,U20A20207,62004184,62004186,and 62234007)the Key-Area Research and Development Program of Guangdong Province (Grant No.2020B010174002)+3 种基金the funding support from University of Science and Technology of China (USTC) (Grant Nos.YD2100002009 and YD2100002010)the Fundamental Research Plan (Grant No.JCKY2020110B010)Collaborative Innovation Program of Hefei Science Center,Chinese Academy of Sciences (Grant No.2022HSC-CIP024)the Opening Project of and the Key Laboratory of Nanodevices and Applications in Suzhou Institute of Nano-Tech and Nano-Bionics of CAS。
文摘Recently,β-Ga_(2)O_(3),an ultra-wide bandgap semiconductor,has shown great potential to be used in power devices blessed with its unique material properties.For instance,the measured average critical field of the vertical Schottky barrier diode(SBD)based onβ-Ga_(2)O_(3) has reached 5.45 MV/cm,and no device in any material has measured a greater before.However,the high electric field of theβ-Ga_(2)O_(3) SBD makes it challenging to manage the electric field distribution and leakage current.Here,we showβ-Ga_(2)O_(3) junction barrier Schottky diode with NiO p-well floating field rings(FFRs).For the central anode,we filled a circular trench array with NiO to reduce the surface field under the Schottky contact between them to reduce the leakage current of the device.For the anode edge,experimental results have demonstrated that the produced NiO/β-Ga_(2)O_(3) heterojunction FFRs enable the spreading of the depletion region,thereby mitigating the crowding effect of electric fields at the anode edge.Additionally,simulation results indicated that the p-NiO field plate structure designed at the edges of the rings and central anode can further reduce the electric field.This work verified the feasibility of the heterojunction FFRs inβ-Ga_(2)O_(3) devices based on the experimental findings and provided ideas for managing the electric field ofβ-Ga_(2)O_(3) SBD.