Hydrodynamic cavitation,as an efficient technique applied in many physical and chemical treatment methods,has been widely used by various industries and in several technological fields.Relevant generators,designed wit...Hydrodynamic cavitation,as an efficient technique applied in many physical and chemical treatment methods,has been widely used by various industries and in several technological fields.Relevant generators,designed with specific structures and parameters,can produce cavitation effects,thereby enabling effective treatment and reasonable transformation of substances.This paper reviews the design principles,performance,and practical applications associated with different types of cavitation generators,aiming to provide theoretical support for the optimization of these systems.It systematically analyzes the underpinning mechanisms and the various factors influencing the cavitation phenomena,also conducting a comparative analysis of the performance of different types of generators.Specific applications dealing with wastewater treatment,chemical reaction acceleration,and other fields are discussed together with the advantages,disadvantages,and applicability of each type of cavitation generator.We also explore research progress in areas such as cavitation stability,energy efficiency,and equipment design upgrades.The study concludes by forecasting the application prospects of intelligent design and computational fluid dynamics(CFD)in optimizing and advancing cavitation generators.It proposes new ideas for the further development of cavitation technology and highlights directions for its widespread future application.展开更多
A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floa...A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floating turbines exhibit six degrees of freedom motion,potentially intensifying the cavitation on the blade surfaces.This study selects three types of oscillatory motions from the six degrees of freedom:roll,yaw,and pitch.Computational fluid dynamics(CFD)methods are used for numerical calculations,and transient simulations of multiphase flow are conducted on the basis of the Reynolds-Averaged Navier-Stokes(RANS)model.Research has revealed strong correlations between flow velocity,the blade tip speed ratio,and cavitation.During oscillatory motion,the motion period and amplitude also significantly impact cavitation.In roll motion,the cavitation rate can increase by up to 59%with decreasing period,whereas in pitch and yaw motions,the increases are 7.57 times and 36%larger,respectively.With an increase in amplitude during roll motion,the cavitation rate can increase by up to 1.08 times,whereas in pitch and yaw motions,the increases are 3.49 times and 45%,respectively.The cavitation rate on the blade surfaces is the highest in pitch motion,followed by roll and yaw motions.展开更多
An orthogonal ultrasonic irradiation system consisting of HIFU with frequency at 1.05 MHz combined with ultrasound with frequency at 28 kHz was applied in this paper.Effect of cavitation was detected by pH-value measu...An orthogonal ultrasonic irradiation system consisting of HIFU with frequency at 1.05 MHz combined with ultrasound with frequency at 28 kHz was applied in this paper.Effect of cavitation was detected by pH-value measurement and conductance measurement.The result shows that the effect of cavitation caused by ultrasound with frequency at 28 kHz is greatly enhanced by HIFU piezoelectricity transducer with frequency at 1.05 MHz.展开更多
Dynamics of a single cavitation bubble in sodium dodecyl sulfate（SDS） aqueous solutions is investigated experimentally and theoretically. The bubble pulsation is measured by a phase-locked integrated imaging techniq...Dynamics of a single cavitation bubble in sodium dodecyl sulfate（SDS） aqueous solutions is investigated experimentally and theoretically. The bubble pulsation is measured by a phase-locked integrated imaging technique,and the ambient radius is obtained by fitting the numerical calculation based on the Rayleigh–Plesset bubble dynamics model to the experimental data. The results show that, under the same driving condition, the ambient radius of the cavitation bubble decreases correspondingly with the increase of SDS concentration within the critical micelle concentration, while the compression ratio of the radius increases, which indicates that the addition of SDS decreases the internal molecular number of the cavitation bubble and increases the power capability of the cavitation bubble. In addition, bubble oscillation increases the concentration of the surfactant molecules on the bubble wall, so that the effect of SDS on a single cavitation bubble is reduced when the SDS concentration is greater than 0.8 m M.展开更多
A double-layered W/Mg structure is expected to be a new generation of nuclear radiation shielding material.The tungsten heavy alloy(W90)and AZ31B Mg alloy were firstly bonded by ultrasonic-assisted soldering using pur...A double-layered W/Mg structure is expected to be a new generation of nuclear radiation shielding material.The tungsten heavy alloy(W90)and AZ31B Mg alloy were firstly bonded by ultrasonic-assisted soldering using pure Sn and Sn-Al filler metal in an atmospheric environment.The influence of ultrasonication time on the microstructure and mechanical properties of the joint was investigated.The typical microstructure of the W90/Sn/Mg joint was W90/Mg_(2)Sn+Sn/Mg_(2)Sn layer/Mg.As the ultrasonication time increased from 2 s to 10 s,the joint width reduced and the thickness of the Mg_(2)Sn layer increased.The shear strength of the joint firstly increased,then flattened,and finally decreased.The joint strength reached the maximum value of 10.5 MPa.The fracture position of the joint changed from the W90/filler metal interface to the Mg_(2)Sn layer.The addition of Al in Sn resulted in the formation of the Al4 W phase at the W/Sn-1Al interface.The W/filler metal interface changed from the semi-coherent interface to the coherent interface and the joint strength increased.As the ultrasonication time was 6 s,the shear strength W90/Sn-1Al/Mg joint reached the maximum value of 24.6 MPa and the joint fractured at two positions:W90/filler metal interface and filler metal.With the further increase of ultrasonication time,the joint strength decreased and the joint fractured in the Mg_(2)Sn layer.展开更多
Sonodynamic therapy(SDT)exhibits promising clinical applications in cancer treatment owing to its ad-vantages,including ultrasonic cavitation effect,mechanical effect,and deep tissue penetration.Titanium dioxide(TiO_(...Sonodynamic therapy(SDT)exhibits promising clinical applications in cancer treatment owing to its ad-vantages,including ultrasonic cavitation effect,mechanical effect,and deep tissue penetration.Titanium dioxide(TiO_(2))nanomaterials,recognized as excellent sonosensitizers,have been extensively studied in cancer SDT.This review first outlines the mechanism of TiO_(2)-based SDT,then systematically discusses the regulation of TiO_(2) sonosensitivity,covering aspects such as morphology,particle size,element doping,defect engineering,heterojunction structure,and interactions with the tumor microenvironment.Further-more,the review generalizes ultrasound-responsive TiO_(2)-based therapeutic modalities for tumor treat-ment,including SDT,SDT combined with chemotherapy,chemodynamic therapy,photothermal therapy,immunotherapy,and treatment visualization.Finally,the review navigates the ongoing challenges and prospects in TiO_(2)-based cancer SDT.展开更多
Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this stud...Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this study,low-intensity pulsed ultrasound(LIPUS),widely used clinically to promote bone healing,was combined with Mg alloy scaffolds to evaluate scaffold degradation under dynamic conditions,in vitro using Hanks’balanced salt solution+BSA solution and in vivo in the femoral condyles of male SD rats.Results showed that LIPUS accelerated the initial degradation of the scaffold in both in vivo and in vitro experiments.In vitro,LIPUS increased BSA adsorption on scaffold surfaces,with adsorption increasing alongside LIPUS intensity.Limited BSA replenishment led to a thin organic-inorganic film that provided weak resistance to corrosive ions,accelerating degradation.Cavitation induced by LIPUS caused microbubble collapse,detaching Ca-P salts from scaffold surfaces.In vivo,LIPUS enhanced cell membrane permeability and activity,promoting the secretion of substances that formed a thicker organic-inorganic composite layer.Continuous material replenishment in the in vivo environment ensured the protective effect of this layer against corrosive ions,while embedded Ca-P salts were less likely to detach.In addition,LIPUS promotes bone modification.These findings highlight the potential of combining LIPUS with Mg alloys to regulate scaffold degradation,offering innovative strategies for clinical bone repair.展开更多
Considering the effect of viscosity-temperature relationship and cavitation of micro-scale film,the influencing factors on hydrodynamic lubrication performance of upstream pumping mechanical seal were investigated bas...Considering the effect of viscosity-temperature relationship and cavitation of micro-scale film,the influencing factors on hydrodynamic lubrication performance of upstream pumping mechanical seal were investigated based on the theory of hydrodynamic lubrication.N-S equation,energy equation,viscosity-temperature equation and vapor transport equation were solved with the finite volume method by using Fluent software,which was performed to analyze the influence of the viscosity-temperature and cavitation effect on hydrodynamic lubrication failure of the film.The research demonstrates that it will lead to the significant difference of the temperature field by considering the coupling of temperature and viscosity.When the film thickness decreases and the rotating speed rises,cavitation regions and viscous friction heat increases,the opening force of the film is also enhanced.However,the growth rate is restricted to the cavitation regions and viscous friction heat,and the opening force begins to decline to a certain extent,and thereby being insufficient to open the surfaces of the seals and leading to the failure of automatic adjustment function and severe wear,lubrication failure occurrs.Through comprehensive research on the influences of viscosity-temperature and cavitation effect on hydrodynamic lubrication performance,the theories of failure and design of upstream pumping mechanical seal are further developed.展开更多
Transdermal drug delivery （TDD） can effectively bypass the first-pass effect. In this paper, ultrasound-facilitated TDD on fresh porcine skin was studied under various acoustic parameters, including frequency, ampli...Transdermal drug delivery （TDD） can effectively bypass the first-pass effect. In this paper, ultrasound-facilitated TDD on fresh porcine skin was studied under various acoustic parameters, including frequency, amplitude, and exposure time. The delivery of yellow-green fluorescent nanoparticles and high molecular weight hyaluronic acid （HA） in the skin samples was observed by laser confocal microscopy and ultraviolet spectrometry, respectively. The results showed that, with the application of ultrasound exposures, the permeability of the skin to these markers （e.g., their penetration depth and concentration） could be raised above its passive diffusion permeability. Moreover, ultrasound-facilitated TDD was also tested with/without the presence of ultrasound contrast agents （UCAs）. When the ultrasound was applied without UCAs, low ultrasound frequency will give a better drug delivery effect than high frequency, but the penetration depth was less likely to exceed 200 p.m. However, with the help of the ultrasound-induced microbubble cavitation effect, both the penetration depth and concentration in the skin were significantly enhanced even more. The best ultrasound-facilitated TDD could be achieved with a drug penetration depth of over 600 p.m, and the penetration concentrations of fluorescent nanoparticles and HA increased up to about 4-5 folds. In order to get better understanding of ultrasound-facilitated TDD, scanning electron microscopy was used to examine the surface morphology of skin samples, which showed that the skin structure changed greatly under the treatment of ultrasound and UCA. The present work suggests that, for TDD applications （e.g., nanoparticle drug carriers, transdermal patches and cosmetics）, protocols and methods presented in this paper are potentially useful.展开更多
The polishing efficiency of the soft abrasive flow(SAF)method is low,which is not in line with the concept of carbon emission reduction in industrial production.To address the above issue,a two-phase fluid multi-physi...The polishing efficiency of the soft abrasive flow(SAF)method is low,which is not in line with the concept of carbon emission reduction in industrial production.To address the above issue,a two-phase fluid multi-physics modeling method for ultrasonic-assisted SAF processing is proposed.The acoustics-fluid coupling mechanic model based on the realizable k-ε model and Helmholtz equation is built to analyze the cavitation effect.The results show that the pro-posed modeling and solution method oriented to ultrasonic-assisted SAF processing have better revealed the flow field evolution mechanism.The turbulence kinetic energy at different ultrasonic frequencies and amplitudes is stud-ied.Simulation results show that the ultrasonic vibration can induce a cavitation effect in the constrained flow chan-nel and promote the turbulence intensity and uniformity of the abrasive flow.A set of comparative polishing experiments with or without ultrasonic vibration are conducted to explore the performance of the proposed method.It can be found that the ultrasonic-assisted SAF method can improve the machining efficiency and uniformity,to achieve the purpose of carbon emission reduction.The relevant result can offer a helpful reference for the SAF method.展开更多
Because of the complication of turbulence＇s mechanism and law as well as the jet pressure in nozzle is difficult to test by experiment, five turbulent models were applied to numerically simulate the turbulent flow fi...Because of the complication of turbulence＇s mechanism and law as well as the jet pressure in nozzle is difficult to test by experiment, five turbulent models were applied to numerically simulate the turbulent flow field in convergent-divergent nozzle. Theory analysis and experiment results of mass flow rates conclude that the RNG k-ε model is the most suitable model. The pressure distribution in the convergent-divergent nozzle was revealed by computational fluid dynamic （CFD） simulating on the turbulent flow field under different pressure conditions. The growing conditions of cavitation bubbles were shown; meanwhile, the phenomena in the experiment could be explained. The differential pres- sure between the upstream and downstream in nozzle throat section can improve the cavitating effect of cavitation water jet.展开更多
Most of the patients with oral and maxillofacial malignancy are in the middle and advanced stages at diagnosis and the incidence rate is increasing in recent years.Chemotherapy alone is difficult to benefit the surviv...Most of the patients with oral and maxillofacial malignancy are in the middle and advanced stages at diagnosis and the incidence rate is increasing in recent years.Chemotherapy alone is difficult to benefit the survival of patients with advanced oral and maxillofacial malignancy.Ultrasound hyperthermia is a new and effective treatment for malignant tumor,which is developing rapidly in addition to conventional treatment.However,at present,ultrasound hyperthermia has not been widely used in the treatment of oral and maxillofacial malignancy.Therefore,formation of a guideline on ultrasound hyperthermia for oral and maxillofacial malignancy is mandatory,in order to promote and standardize the clinical practice of ultrasound hyperthermia in this field,and improve the long-term survival rate and quality of life of patients.展开更多
文摘Hydrodynamic cavitation,as an efficient technique applied in many physical and chemical treatment methods,has been widely used by various industries and in several technological fields.Relevant generators,designed with specific structures and parameters,can produce cavitation effects,thereby enabling effective treatment and reasonable transformation of substances.This paper reviews the design principles,performance,and practical applications associated with different types of cavitation generators,aiming to provide theoretical support for the optimization of these systems.It systematically analyzes the underpinning mechanisms and the various factors influencing the cavitation phenomena,also conducting a comparative analysis of the performance of different types of generators.Specific applications dealing with wastewater treatment,chemical reaction acceleration,and other fields are discussed together with the advantages,disadvantages,and applicability of each type of cavitation generator.We also explore research progress in areas such as cavitation stability,energy efficiency,and equipment design upgrades.The study concludes by forecasting the application prospects of intelligent design and computational fluid dynamics(CFD)in optimizing and advancing cavitation generators.It proposes new ideas for the further development of cavitation technology and highlights directions for its widespread future application.
基金supported by the National Natural Science Foundation of China(Grant No.52171261).
文摘A floating horizontal-axis tidal current turbine(HATT)is an underwater power generation device where cavitation inevitably occurs on blade surfaces,severely affecting a turbine’s lifespan.Under wave action,these floating turbines exhibit six degrees of freedom motion,potentially intensifying the cavitation on the blade surfaces.This study selects three types of oscillatory motions from the six degrees of freedom:roll,yaw,and pitch.Computational fluid dynamics(CFD)methods are used for numerical calculations,and transient simulations of multiphase flow are conducted on the basis of the Reynolds-Averaged Navier-Stokes(RANS)model.Research has revealed strong correlations between flow velocity,the blade tip speed ratio,and cavitation.During oscillatory motion,the motion period and amplitude also significantly impact cavitation.In roll motion,the cavitation rate can increase by up to 59%with decreasing period,whereas in pitch and yaw motions,the increases are 7.57 times and 36%larger,respectively.With an increase in amplitude during roll motion,the cavitation rate can increase by up to 1.08 times,whereas in pitch and yaw motions,the increases are 3.49 times and 45%,respectively.The cavitation rate on the blade surfaces is the highest in pitch motion,followed by roll and yaw motions.
基金supported by National Natural Science Foundation of China(10574038)development project of high-tech industry of universities in Jiangsu(JHB05-08)Changzhou scientific and technological bureau(CE2005026).
文摘An orthogonal ultrasonic irradiation system consisting of HIFU with frequency at 1.05 MHz combined with ultrasound with frequency at 28 kHz was applied in this paper.Effect of cavitation was detected by pH-value measurement and conductance measurement.The result shows that the effect of cavitation caused by ultrasound with frequency at 28 kHz is greatly enhanced by HIFU piezoelectricity transducer with frequency at 1.05 MHz.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11334005 and 11574150
文摘Dynamics of a single cavitation bubble in sodium dodecyl sulfate（SDS） aqueous solutions is investigated experimentally and theoretically. The bubble pulsation is measured by a phase-locked integrated imaging technique,and the ambient radius is obtained by fitting the numerical calculation based on the Rayleigh–Plesset bubble dynamics model to the experimental data. The results show that, under the same driving condition, the ambient radius of the cavitation bubble decreases correspondingly with the increase of SDS concentration within the critical micelle concentration, while the compression ratio of the radius increases, which indicates that the addition of SDS decreases the internal molecular number of the cavitation bubble and increases the power capability of the cavitation bubble. In addition, bubble oscillation increases the concentration of the surfactant molecules on the bubble wall, so that the effect of SDS on a single cavitation bubble is reduced when the SDS concentration is greater than 0.8 m M.
基金supported by the National Natural Science Foundation of China(nos.52105330 and 52175307)the Natural Science Foundation of Shandong Province(no.ZR2020QE175)the Taishan Scholars Foundation of Shandong Province(no.tsqn201812128).
文摘A double-layered W/Mg structure is expected to be a new generation of nuclear radiation shielding material.The tungsten heavy alloy(W90)and AZ31B Mg alloy were firstly bonded by ultrasonic-assisted soldering using pure Sn and Sn-Al filler metal in an atmospheric environment.The influence of ultrasonication time on the microstructure and mechanical properties of the joint was investigated.The typical microstructure of the W90/Sn/Mg joint was W90/Mg_(2)Sn+Sn/Mg_(2)Sn layer/Mg.As the ultrasonication time increased from 2 s to 10 s,the joint width reduced and the thickness of the Mg_(2)Sn layer increased.The shear strength of the joint firstly increased,then flattened,and finally decreased.The joint strength reached the maximum value of 10.5 MPa.The fracture position of the joint changed from the W90/filler metal interface to the Mg_(2)Sn layer.The addition of Al in Sn resulted in the formation of the Al4 W phase at the W/Sn-1Al interface.The W/filler metal interface changed from the semi-coherent interface to the coherent interface and the joint strength increased.As the ultrasonication time was 6 s,the shear strength W90/Sn-1Al/Mg joint reached the maximum value of 24.6 MPa and the joint fractured at two positions:W90/filler metal interface and filler metal.With the further increase of ultrasonication time,the joint strength decreased and the joint fractured in the Mg_(2)Sn layer.
基金supported by the National Natural Science Foundation of China(Nos.31971292,32025021,32171359,32111540257,32311530040)the Zhejiang Province Financial Supporting(No.2020c03110)the Key Scientific and Technological Special Project of Ningbo City(Nos.2020Z094,2023Z189).
文摘Sonodynamic therapy(SDT)exhibits promising clinical applications in cancer treatment owing to its ad-vantages,including ultrasonic cavitation effect,mechanical effect,and deep tissue penetration.Titanium dioxide(TiO_(2))nanomaterials,recognized as excellent sonosensitizers,have been extensively studied in cancer SDT.This review first outlines the mechanism of TiO_(2)-based SDT,then systematically discusses the regulation of TiO_(2) sonosensitivity,covering aspects such as morphology,particle size,element doping,defect engineering,heterojunction structure,and interactions with the tumor microenvironment.Further-more,the review generalizes ultrasound-responsive TiO_(2)-based therapeutic modalities for tumor treat-ment,including SDT,SDT combined with chemotherapy,chemodynamic therapy,photothermal therapy,immunotherapy,and treatment visualization.Finally,the review navigates the ongoing challenges and prospects in TiO_(2)-based cancer SDT.
基金supported by Project of Zhongyuan Critical Metals Laboratory(GJJSGFYQ202406)National Natural Science Foundation of China(51701184,51671175)Young Backbone Teachers Foundation of Zhengzhou University.
文摘Magnesium(Mg)alloys have excellent biocompatibility and biodegradability,making them promising for clinical applications.However,their rapid degradation compared to bone healing limits their effectiveness.In this study,low-intensity pulsed ultrasound(LIPUS),widely used clinically to promote bone healing,was combined with Mg alloy scaffolds to evaluate scaffold degradation under dynamic conditions,in vitro using Hanks’balanced salt solution+BSA solution and in vivo in the femoral condyles of male SD rats.Results showed that LIPUS accelerated the initial degradation of the scaffold in both in vivo and in vitro experiments.In vitro,LIPUS increased BSA adsorption on scaffold surfaces,with adsorption increasing alongside LIPUS intensity.Limited BSA replenishment led to a thin organic-inorganic film that provided weak resistance to corrosive ions,accelerating degradation.Cavitation induced by LIPUS caused microbubble collapse,detaching Ca-P salts from scaffold surfaces.In vivo,LIPUS enhanced cell membrane permeability and activity,promoting the secretion of substances that formed a thicker organic-inorganic composite layer.Continuous material replenishment in the in vivo environment ensured the protective effect of this layer against corrosive ions,while embedded Ca-P salts were less likely to detach.In addition,LIPUS promotes bone modification.These findings highlight the potential of combining LIPUS with Mg alloys to regulate scaffold degradation,offering innovative strategies for clinical bone repair.
基金National Natural Science Foundation of China(Grant No.51279067)
文摘Considering the effect of viscosity-temperature relationship and cavitation of micro-scale film,the influencing factors on hydrodynamic lubrication performance of upstream pumping mechanical seal were investigated based on the theory of hydrodynamic lubrication.N-S equation,energy equation,viscosity-temperature equation and vapor transport equation were solved with the finite volume method by using Fluent software,which was performed to analyze the influence of the viscosity-temperature and cavitation effect on hydrodynamic lubrication failure of the film.The research demonstrates that it will lead to the significant difference of the temperature field by considering the coupling of temperature and viscosity.When the film thickness decreases and the rotating speed rises,cavitation regions and viscous friction heat increases,the opening force of the film is also enhanced.However,the growth rate is restricted to the cavitation regions and viscous friction heat,and the opening force begins to decline to a certain extent,and thereby being insufficient to open the surfaces of the seals and leading to the failure of automatic adjustment function and severe wear,lubrication failure occurrs.Through comprehensive research on the influences of viscosity-temperature and cavitation effect on hydrodynamic lubrication performance,the theories of failure and design of upstream pumping mechanical seal are further developed.
基金Project partially supported by the National Natural Science Foundation of China(Grant Nos.81127901,81227004,81473692,81673995,11374155,11574156,11274170,11274176,11474001,11474161,11474166,and 11674173)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK2011812)+1 种基金the Fundamental Research Funds for the Central Universitiesthe National High-Tech Research and Development Program of China(Grant No.2012AA022702)
文摘Transdermal drug delivery （TDD） can effectively bypass the first-pass effect. In this paper, ultrasound-facilitated TDD on fresh porcine skin was studied under various acoustic parameters, including frequency, amplitude, and exposure time. The delivery of yellow-green fluorescent nanoparticles and high molecular weight hyaluronic acid （HA） in the skin samples was observed by laser confocal microscopy and ultraviolet spectrometry, respectively. The results showed that, with the application of ultrasound exposures, the permeability of the skin to these markers （e.g., their penetration depth and concentration） could be raised above its passive diffusion permeability. Moreover, ultrasound-facilitated TDD was also tested with/without the presence of ultrasound contrast agents （UCAs）. When the ultrasound was applied without UCAs, low ultrasound frequency will give a better drug delivery effect than high frequency, but the penetration depth was less likely to exceed 200 p.m. However, with the help of the ultrasound-induced microbubble cavitation effect, both the penetration depth and concentration in the skin were significantly enhanced even more. The best ultrasound-facilitated TDD could be achieved with a drug penetration depth of over 600 p.m, and the penetration concentrations of fluorescent nanoparticles and HA increased up to about 4-5 folds. In order to get better understanding of ultrasound-facilitated TDD, scanning electron microscopy was used to examine the surface morphology of skin samples, which showed that the skin structure changed greatly under the treatment of ultrasound and UCA. The present work suggests that, for TDD applications （e.g., nanoparticle drug carriers, transdermal patches and cosmetics）, protocols and methods presented in this paper are potentially useful.
基金Supported by National Natural Science Foundation of China(Grant No.52175124)Zhejiang Provincial Natural Science Foundation(Grant No.LZ21E050003)Fundamental Research Funds for the Zhejiang Universities(Grant No.RF-C2020004).
文摘The polishing efficiency of the soft abrasive flow(SAF)method is low,which is not in line with the concept of carbon emission reduction in industrial production.To address the above issue,a two-phase fluid multi-physics modeling method for ultrasonic-assisted SAF processing is proposed.The acoustics-fluid coupling mechanic model based on the realizable k-ε model and Helmholtz equation is built to analyze the cavitation effect.The results show that the pro-posed modeling and solution method oriented to ultrasonic-assisted SAF processing have better revealed the flow field evolution mechanism.The turbulence kinetic energy at different ultrasonic frequencies and amplitudes is stud-ied.Simulation results show that the ultrasonic vibration can induce a cavitation effect in the constrained flow chan-nel and promote the turbulence intensity and uniformity of the abrasive flow.A set of comparative polishing experiments with or without ultrasonic vibration are conducted to explore the performance of the proposed method.It can be found that the ultrasonic-assisted SAF method can improve the machining efficiency and uniformity,to achieve the purpose of carbon emission reduction.The relevant result can offer a helpful reference for the SAF method.
基金Supported by the National Natural Science Foundation of China (50621403,50604019)Program for New Century Excellent Talents in Univer sity(NCET-06-0767)
文摘Because of the complication of turbulence＇s mechanism and law as well as the jet pressure in nozzle is difficult to test by experiment, five turbulent models were applied to numerically simulate the turbulent flow field in convergent-divergent nozzle. Theory analysis and experiment results of mass flow rates conclude that the RNG k-ε model is the most suitable model. The pressure distribution in the convergent-divergent nozzle was revealed by computational fluid dynamic （CFD） simulating on the turbulent flow field under different pressure conditions. The growing conditions of cavitation bubbles were shown; meanwhile, the phenomena in the experiment could be explained. The differential pres- sure between the upstream and downstream in nozzle throat section can improve the cavitating effect of cavitation water jet.
文摘Most of the patients with oral and maxillofacial malignancy are in the middle and advanced stages at diagnosis and the incidence rate is increasing in recent years.Chemotherapy alone is difficult to benefit the survival of patients with advanced oral and maxillofacial malignancy.Ultrasound hyperthermia is a new and effective treatment for malignant tumor,which is developing rapidly in addition to conventional treatment.However,at present,ultrasound hyperthermia has not been widely used in the treatment of oral and maxillofacial malignancy.Therefore,formation of a guideline on ultrasound hyperthermia for oral and maxillofacial malignancy is mandatory,in order to promote and standardize the clinical practice of ultrasound hyperthermia in this field,and improve the long-term survival rate and quality of life of patients.
