Objective To observe the therapeutic effect of acupuncture combined with atomized herbal medicine in the treatment of protrusion of lumbar intervertebral disc. Methods A total of 211 patients with lumbar intervertebra...Objective To observe the therapeutic effect of acupuncture combined with atomized herbal medicine in the treatment of protrusion of lumbar intervertebral disc. Methods A total of 211 patients with lumbar intervertebral disc protrusion were randomized into two groups, with 106 cases being in trealment group and 105 in control group. The treatment was given once everyday, 12 days as one course of treatment. After two courses of treatment, the results were analyzed. Results The curative rate was 97.1% in the treatment group and 81.0% in the control group. Conclusion Acupuncture together with herbal medicine for the protrusion of lumbar intervetebral disc was better in effect than acupuncture only.展开更多
The heat transfer problem of the atomized droplets during high velocity arc spraying (HVAS) was modeled and solved by a numerical method using a Fe-Al alloy, and the influences of several important process parameters ...The heat transfer problem of the atomized droplets during high velocity arc spraying (HVAS) was modeled and solved by a numerical method using a Fe-Al alloy, and the influences of several important process parameters on the heat transfer behaviors of the atomized droplets were analyzed. The results show that the initial cooling rates of different size droplets range from 105 to 107 K/s, thus producing the coating microstructure with the features of rapid solidification. The droplet size, atomization gas pressure and droplet superheat have great influences on the heat transfer behavior of the droplet. The droplet temperature and cooling rate are much sensitive to the droplet sizes, but insensitive to the atomization gas pressure and droplet superheat. It can be predicted that the properties of HVAS coatings will be improved by decreasing droplet size as well as increasing atomization gas pressure and droplet superheat in certain extents.展开更多
In spray atomization and codeposition, a molten stream of metal is disintegrated into a fine dispersion of droplets by high velocity gas jets. The resulting semi-solidified droplets are directed towards a substrate wh...In spray atomization and codeposition, a molten stream of metal is disintegrated into a fine dispersion of droplets by high velocity gas jets. The resulting semi-solidified droplets are directed towards a substrate where they impact and collect as rapidly solidified splats. Relatively high rates of solidification are achieved as a result of the thinness of the splats and the rapid heat extraction during flight and upon impacting with the substrate. The processing method uses codeposition of the metallic semi-solidified droplets (metallic matrix) with the injected reinforcement ceramic particles. In the present paper, the microstructures, mechanical properties, interfacial properties, thermal stability and aging behaviour of spray atomized and codeposited Al-Li-X MMC's (injected X=SiC, Al2O3) are reported and correlated to the processing conditions.展开更多
The influence of the injection of reinforcing particles (for the production of metal matrix composites and of the droplets-to-substrate heat transfer on the resulting microstructural uniformity of spray atomized and c...The influence of the injection of reinforcing particles (for the production of metal matrix composites and of the droplets-to-substrate heat transfer on the resulting microstructural uniformity of spray atomized and codeposited composite material is analyzed. The reinforcement particles injection velocity has to be limited between an upper and a lower critical values. in order to ensure entrapment into the matrix droplets in flight. The thermal history of the injected droplets during the deposition stage is calculated with the assumption that the in-flight solidifying droplets reach the substrate while containing still at least 20% liquid volume fraction, in order to avoid porosity of the deposited material. The substrate to pouring-tube orifice distance where that condition is achieved depends strongly on the atomization pressure and the convective heat transfer coefficient of the substrate. It is demonstrated that 'tailoring' the microstructures and the reinforcement volume percent in the deposited material is feasible. The critical process parameters : the atomization pressure, the melt flow rate. the substrate to pouring-tube orifice distance, the reinforcement particles injection location and rate can all be adequately chosen in order to obtain any desired microstructure, grain size, reinforcement volume percent, with the additional benefit, if wanted, of rapid solidification processing展开更多
A combustion tube experiment platform was designed and used to study the inerting conditions and capacity of entrained atomized water on premixed methane–air flame. The structure of a laminar flame of premixed methan...A combustion tube experiment platform was designed and used to study the inerting conditions and capacity of entrained atomized water on premixed methane–air flame. The structure of a laminar flame of premixed methane–air gas and the process of interaction between atomized water and flame was recorded, and the rules of combustion velocity, stability and strength rate of laminar flame were experimentally studied. The inerting process and mechanism was analyzed, and the characteristics of inerting premixed methane–air gas within explosion limits by atomized water were acquired. The research results show that: for the premixed methane–air gas with a concentration of 7%, the minimum inerting atomized water flux is 20.8 m L/(m2min); for the premixed methane–air gas with a concentration of 9%, the minimum inerting atomized water flux is 32.9 m L/(m2min); for the premixed methane–air gas with a concentration of 11%, the minimum inerting atomized water flux is 44.6 m L/(m2min). The research results are significant for extinguishing methane flame and inhibiting of methane explosion using atomized water.展开更多
Fluid mechanics, heat transfer and liquid-to-solid phase transformation are assessed in optimizing the spray atomization and codeposition process parameters for size refinement and microstructural uniformity of the de...Fluid mechanics, heat transfer and liquid-to-solid phase transformation are assessed in optimizing the spray atomization and codeposition process parameters for size refinement and microstructural uniformity of the deposited material. Atomization gas velocities, atomized droplets velocities, convective heat transfer coefficients, thermal histories of the solidifying droplets, freezing rates, fraction solid evolution and solid-liquid interface propagation velocity are calculated. The influence, on the deposit microstructural features, of process parameters like the atomization gas pressure, the pouring tube orifice diameter, the geometrical features of the atomization device,the potency of , pre-existing or injected as reinforcement, nucleation sites, the wetting angle between the liquid melt bnd impurity particles acting as preferred nucleation sites, the in-flight distance of the solidifying droplets in the atomization chamber, i5 evaluated. As a result of the evaluation, appropriate choice of the adjustable process parameters for the production of powders and/or deposits with desired grain size and microstructure, can be made.展开更多
Powder extrusion, which is based on the superplastic behavior of Zn-22%A1 eutectoid alloy, was proposed to reduce the forming load and promises to provide fine microstructures in the manufacture of miniature helical g...Powder extrusion, which is based on the superplastic behavior of Zn-22%A1 eutectoid alloy, was proposed to reduce the forming load and promises to provide fine microstructures in the manufacture of miniature helical gears. The specifications of the helical gears were as follows： module, 0.3; number of teeth, 12; and helix angle, 15°. Compacted powders were consolidated by sintering and solution heat treatment. The consolidated billets consisted of lamellar and fine-grained microstructures. Extrusion experiments were carried out under the following conditions： temperature, 250 ℃; strain rates, 2.36× 10-3 s^-1 and 1.18× 10^-1 s-1. The mechanical properties of the extruded helical gears were investigated by measurement of the Vickers hardness and extrusion load, and by scanning electron microscopy.展开更多
Numerical simulation was performed in an atomizing chamber to investigate the movements and thermal states of the atomized metal droplets in the spray forming process. The velocity, temperature and solid fractions of ...Numerical simulation was performed in an atomizing chamber to investigate the movements and thermal states of the atomized metal droplets in the spray forming process. The velocity, temperature and solid fractions of metal droplets with different diameters and under different atomizing pressures were investigated. The results indicate that a higher atomizing pressure results in the increased flying velocity of the metal droplets and a decrease in the cone-shaped angle formed by their flight paths. Synchronously, the cooling of the metal droplets is accelerated and the time of the complete solidification process is shortened. Under the same atomization pressure, large metal droplets have a lower flying speed and a lower rate of temperature decrease in the atomizing chamber than small metal droplets. In addition, metal droplets flying along the edge of the atomizing region cool faster than those flying in the core region.展开更多
Water atomized Fe Ni Mo steel powder, was utilized as base powder for designing powder mixtures for warm pressing. The warm pressing and sintering behaviours of the powder mixtures were studied. The results show that,...Water atomized Fe Ni Mo steel powder, was utilized as base powder for designing powder mixtures for warm pressing. The warm pressing and sintering behaviours of the powder mixtures were studied. The results show that, compared with the pressing at room temperature, the green density gain by warm pressing is within a range of 0.10 0.19 g/cm 3 and reduction in spring back is 30% 40% of the ambient, and maximum green density of 7.32 g/cm 3 at 735 MPa is obtained as the graphite mass fraction is 0.8%. It was found that sintered densities of the compacts were reduced slightly due to releasing of elastic stress stored in the compacts during sintering. The warm pressing of steel powders gives evidence for substituting the traditional double pressing and double sintering process.展开更多
Objective: As a Chinese drugs preparation to clear heat and remove toxicity, Shuanghuanglian (SHL) has been widely used, but the clinical efficacy and safety of SHL on chronic pharyngitis remain unclear, especially th...Objective: As a Chinese drugs preparation to clear heat and remove toxicity, Shuanghuanglian (SHL) has been widely used, but the clinical efficacy and safety of SHL on chronic pharyngitis remain unclear, especially the application of atomized inhalation of SHL need to be verified. The aim of this study was to evaluate its clinical efficacy and safety for chronic pharyngitis. Methods: From the Cochrane Library, Pubmed, EMbase, Wanfang Datebase, CNKI (China National Knowledge Infrastructure), VIP (Chinese Scientifc Journals Database), CBM (Chinese Biomedicine Database), We got the qualified randomized controlled trials(RCTs) and adopted RevMan5.3 software and the risk of bias tool according to the Cochrane to perform a metaanalysis. Results: Ten RCTs, a total of 950 cases (involving 472 cases in SHL group and 478 in control group) were included. The results showed that the clinical efficacy in SHL group was superior to control group [Chi2=5.61, 95%CI (4.29, 11.43), P<0.05], and four literatures reported no obvious adverse reactions in SHL group. Conclusion: Application of atomized inhalation of SHL may have a potential advantage in treating chronic pharyngitis. However, due to the limitation of the quality and sample size of those studies, the accuracy of the result should be treated with caution, higher standardized researches are required to justify the conclusion.展开更多
Modeling and simulation have been carried out for Al-Pb alloys to investigate the Brownian coagulation effect on the microstructure development in a gas-atomized drop during the liquid-liquid decomposition. The result...Modeling and simulation have been carried out for Al-Pb alloys to investigate the Brownian coagulation effect on the microstructure development in a gas-atomized drop during the liquid-liquid decomposition. The results indicate that Brownian coagulation has a weak effect on the nucleation and a relatively strong effect on coarsening the minority phase droplets. The influence of Brownian coagulation on the liquid-liquid decomposition decreases with the increase in the diameter （or the decrease in the cooling rate） of the atomized drop.展开更多
Gas-atomized pure metal or alloy powders are widely used as raw material in the preparation of high performance materials by powder metallurgy route（compaction and sintering）. However, cold compactibility of gas-ato...Gas-atomized pure metal or alloy powders are widely used as raw material in the preparation of high performance materials by powder metallurgy route（compaction and sintering）. However, cold compactibility of gas-atomized Al-Si alloy powder is inhibited due to the high strength as a result of the refined Si phases and the supersaturated Al matrix. The effect of annealing on improving the compactibility of Al-Si alloy powder was studied. The densification was investigated by the HECKEL compaction equation in terms of deformation capacity. Moreover, the microstructures and bending fracture surfaces of the green compacts were examined to clarify the densification behavior. The results show that a maximum relative density of 96.1% is obtained when the powder is annealed at 400 °C. The deformation capacity is significantly improved by annealing treatment due to the softening of Al matrix, precipitation of supersaturated Si phases, dissolution of needle-like eutectic phase, and spheroidization of Si phases.展开更多
The microstructural evolution of the gas atomized Fe-25Cr-3.2C powders was investigated by using optical microscope, scanning electron microscope, and X-ray diffraction. The experimental results showed that the atomiz...The microstructural evolution of the gas atomized Fe-25Cr-3.2C powders was investigated by using optical microscope, scanning electron microscope, and X-ray diffraction. The experimental results showed that the atomized Fe-25Cr-3.2C powders were mainly composed of austenite and （Fe,Cr）7 C3 carbide. Eutectic microstructure was developed in the larger particles, whereas dendritic microstrueture was obtained in the particles with diameter less than 38 μm. The reason for microstructure change should be the difference of nucleation undercooling for particles.展开更多
Effects of discharge mode, voltage applied, size of the nozzle discharge electrode and flow rate of water on the generation of hydroxyl radical were investigated in air discharge with atomized water, by using optical ...Effects of discharge mode, voltage applied, size of the nozzle discharge electrode and flow rate of water on the generation of hydroxyl radical were investigated in air discharge with atomized water, by using optical emission spectroscopy （OES）. Water was injected into the discharge region through the discharge nozzle electrode, and a large amount of fine water drops, formed and distributed in the discharge region, corona discharge was more effective to generate were observed. It was found that negative DC the hydroxyl radicals in comparison to positive DC corona discharge or negative pulsed discharge. A larger outer diameter of the nozzle electrode or a stronger electric field is beneficial for hydroxyl-radical generation. Moreover, there is a critical value in the flow rate of atomized water against the discharge voltage. Below this critical value, hydroxyl-radical generation increases with the increase in flow rate of the water, while above this value, it decreases. In addition, it is observed that OES from the discharge is mainly in the ultraviolet domain. The results are helpful in the study of the mechanism and application of plasma in pollution-control in either air or water.展开更多
An unprecedentedly short milling time of 30 s was applied to gas-atomized MnAl powder in order to develop permanent magnet properties and,in particular,coercivity.It is shown that such a short processing time followed...An unprecedentedly short milling time of 30 s was applied to gas-atomized MnAl powder in order to develop permanent magnet properties and,in particular,coercivity.It is shown that such a short processing time followed by annealing results in efficient nanostructuring and controlled phase transformation.The defects resulting from the microstrain induced during milling,together with the creation of the bphase during post-annealing,act as pinning centers resulting in an enhanced coercivity.This study shows the importance of finding a balance between the formation of the ferromagnetic s-MnAl phase and the bphase in order to establish a compromise between magnetization and coercivity.A coercivity as high as 4.2 kOe(1 Oe=79.6 A·m^-1)was obtained after milling(30 s)and annealing,which is comparable to values previously reported in the literature for milling times exceeding 20 h.This reduction of the postannealing temperature by 75℃ for the as-milled powder and a 2.5-fold increase in coercivity,while maintaining practically unchanged the remanence of the annealed gas-atomized material,opens a new path for the synthesis of isotropic MnAl-based powder.展开更多
The fine structure of hydrogen storage alloy powders MiNi4.3-xCoxMr0.4AI0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis metho...The fine structure of hydrogen storage alloy powders MiNi4.3-xCoxMr0.4AI0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis method. Two sets of CaCu5-type crystal constants were observed in the studied alloys and one set was larger than the other. With decreasing powder radius the solidification rate of powder increased, and so did the percentage of a particle part with larger crystal constants. The reason why there were two sets of crystal constants might be the difference of solidification rate between the outside and inside of a particle.展开更多
In the precision cutting of difficult-to-process metals,surface thermal damage to a workpiece is a significant technical challenge.Although clean minimum quantity lubrication(MQL)technology,which replaces traditional ...In the precision cutting of difficult-to-process metals,surface thermal damage to a workpiece is a significant technical challenge.Although clean minimum quantity lubrication(MQL)technology,which replaces traditional pouring cooling,is used,inadequate heat dissipation remains an issue.Cryogenic air MQL(CAMQL),an eco-friendly technology,can enhance the heat transfer performance of the lubricating film in the cutting zone,offering excellent cooling and lubrication effects.However,the influence of jet and temperature parameters on the average particle size and distribution characteristics of atomized droplets is not well understood.This study first analyzes the evolution of lubricant physical properties and establishes a quantitative mapping relationship between cryogenic air temperature and physical parameters of lubricant.Next,the unstable fluctuation in the annular liquid film at the two-phase flow nozzle exit is observed and analyzed.A thickness model of annular liquid film is developed,revealing the effect of airflow field on the annular liquid film.Finally,a model for the average particle size of atomized droplets under CAMQL is established.Numerical analysis and validation experiments under different working conditions show that the measured values align with the theoretical values.Under an air pressure of 0.4 MPa and an air flow temperature of−50℃,the droplet particle size is 133.5μm,with an error of 8.2%.The effect of air pressure on particle size is greater than that of air flow temperature.Additionally,the distribution spans of droplet size under different conditions are analyzed,and the results demonstrated that low temperatures help shorten the interval between particle sizes and improve the relative uniformity of particle size distribution.This research provides a theoretical basis for the application of CAMQL technology in the cutting process.展开更多
In this article, the unified mathematical model for splash droplets and suspended mist of atomized flow was established, which classifies the atomized sources into the splash source and the suspended source. For the s...In this article, the unified mathematical model for splash droplets and suspended mist of atomized flow was established, which classifies the atomized sources into the splash source and the suspended source. For the splash source, the Lagrangian method was used to simulate the random motion of splash water droplets, and for the suspended source the theory of air-water two-phase flow was used to simulate the mist flow moving in particle clouds. The rainfall intensity of the atomized flow was obtained by summarizing the rainfall intensities relative to the above two types of atomized sources. Both experimental data and prototype observation data were used for the verification of the mathematical model. For both the distribution of rainfall intensity, and the outer edge of the atomized flow, the simulation results are in agreement with the experimental data or prototype observation data.展开更多
Atomized flow is an unnatural two-phase flow produced while water discharges in water release structures. This flow might threaten the normal operation of hydraulic and hydroelectric installations owing to the unnatur...Atomized flow is an unnatural two-phase flow produced while water discharges in water release structures. This flow might threaten the normal operation of hydraulic and hydroelectric installations owing to the unnatural and high-density rain as well as the unnatural and dirty mist. The splash region, the region with the highest rain intensity, hence should receive much attention during the design and operation of the hydraulic and hydroelectric installations. In this paper rain intensity distribution in the splash region of the atomized flow is investigated experimentally, and the method of random simulation is used to predict the rain intensity distribution in the splash region.展开更多
Slit type bucket is one kind of flip bucket for energy dissipation generally used in the hydraulic project. In this paper the atomized flow produced behind this energy dis sipator is analyzed, a numerical model for th...Slit type bucket is one kind of flip bucket for energy dissipation generally used in the hydraulic project. In this paper the atomized flow produced behind this energy dis sipator is analyzed, a numerical model for the aerated jet con sidering air entrainment and air resistance force is suggested, and simulation of the rain resulted by the atomized flow is also discussed. Furthermore, the prototype observation data for the atomized flow of Dongjiang Hydropower Station is used to verify the model suggested.展开更多
文摘Objective To observe the therapeutic effect of acupuncture combined with atomized herbal medicine in the treatment of protrusion of lumbar intervertebral disc. Methods A total of 211 patients with lumbar intervertebral disc protrusion were randomized into two groups, with 106 cases being in trealment group and 105 in control group. The treatment was given once everyday, 12 days as one course of treatment. After two courses of treatment, the results were analyzed. Results The curative rate was 97.1% in the treatment group and 81.0% in the control group. Conclusion Acupuncture together with herbal medicine for the protrusion of lumbar intervetebral disc was better in effect than acupuncture only.
基金Project (50235030) supported by the National Natural Science Foundation of China
文摘The heat transfer problem of the atomized droplets during high velocity arc spraying (HVAS) was modeled and solved by a numerical method using a Fe-Al alloy, and the influences of several important process parameters on the heat transfer behaviors of the atomized droplets were analyzed. The results show that the initial cooling rates of different size droplets range from 105 to 107 K/s, thus producing the coating microstructure with the features of rapid solidification. The droplet size, atomization gas pressure and droplet superheat have great influences on the heat transfer behavior of the droplet. The droplet temperature and cooling rate are much sensitive to the droplet sizes, but insensitive to the atomization gas pressure and droplet superheat. It can be predicted that the properties of HVAS coatings will be improved by decreasing droplet size as well as increasing atomization gas pressure and droplet superheat in certain extents.
文摘In spray atomization and codeposition, a molten stream of metal is disintegrated into a fine dispersion of droplets by high velocity gas jets. The resulting semi-solidified droplets are directed towards a substrate where they impact and collect as rapidly solidified splats. Relatively high rates of solidification are achieved as a result of the thinness of the splats and the rapid heat extraction during flight and upon impacting with the substrate. The processing method uses codeposition of the metallic semi-solidified droplets (metallic matrix) with the injected reinforcement ceramic particles. In the present paper, the microstructures, mechanical properties, interfacial properties, thermal stability and aging behaviour of spray atomized and codeposited Al-Li-X MMC's (injected X=SiC, Al2O3) are reported and correlated to the processing conditions.
文摘The influence of the injection of reinforcing particles (for the production of metal matrix composites and of the droplets-to-substrate heat transfer on the resulting microstructural uniformity of spray atomized and codeposited composite material is analyzed. The reinforcement particles injection velocity has to be limited between an upper and a lower critical values. in order to ensure entrapment into the matrix droplets in flight. The thermal history of the injected droplets during the deposition stage is calculated with the assumption that the in-flight solidifying droplets reach the substrate while containing still at least 20% liquid volume fraction, in order to avoid porosity of the deposited material. The substrate to pouring-tube orifice distance where that condition is achieved depends strongly on the atomization pressure and the convective heat transfer coefficient of the substrate. It is demonstrated that 'tailoring' the microstructures and the reinforcement volume percent in the deposited material is feasible. The critical process parameters : the atomization pressure, the melt flow rate. the substrate to pouring-tube orifice distance, the reinforcement particles injection location and rate can all be adequately chosen in order to obtain any desired microstructure, grain size, reinforcement volume percent, with the additional benefit, if wanted, of rapid solidification processing
基金supported by the National Natural Science Foundation of China(No.51304006)the Natural Science Foundation of Anhui Province(No.1408085QE87)the Training Fund for Youth Backbones of Anhui University of Science&Technology(No.20120012)
文摘A combustion tube experiment platform was designed and used to study the inerting conditions and capacity of entrained atomized water on premixed methane–air flame. The structure of a laminar flame of premixed methane–air gas and the process of interaction between atomized water and flame was recorded, and the rules of combustion velocity, stability and strength rate of laminar flame were experimentally studied. The inerting process and mechanism was analyzed, and the characteristics of inerting premixed methane–air gas within explosion limits by atomized water were acquired. The research results show that: for the premixed methane–air gas with a concentration of 7%, the minimum inerting atomized water flux is 20.8 m L/(m2min); for the premixed methane–air gas with a concentration of 9%, the minimum inerting atomized water flux is 32.9 m L/(m2min); for the premixed methane–air gas with a concentration of 11%, the minimum inerting atomized water flux is 44.6 m L/(m2min). The research results are significant for extinguishing methane flame and inhibiting of methane explosion using atomized water.
文摘Fluid mechanics, heat transfer and liquid-to-solid phase transformation are assessed in optimizing the spray atomization and codeposition process parameters for size refinement and microstructural uniformity of the deposited material. Atomization gas velocities, atomized droplets velocities, convective heat transfer coefficients, thermal histories of the solidifying droplets, freezing rates, fraction solid evolution and solid-liquid interface propagation velocity are calculated. The influence, on the deposit microstructural features, of process parameters like the atomization gas pressure, the pouring tube orifice diameter, the geometrical features of the atomization device,the potency of , pre-existing or injected as reinforcement, nucleation sites, the wetting angle between the liquid melt bnd impurity particles acting as preferred nucleation sites, the in-flight distance of the solidifying droplets in the atomization chamber, i5 evaluated. As a result of the evaluation, appropriate choice of the adjustable process parameters for the production of powders and/or deposits with desired grain size and microstructure, can be made.
基金Project (2010-0008-277) supported by the NCRC (National Core Research Center) Program through the National Research Foundation of Korea,funded by the Ministry of Education,Science,and TechnologyProject (NRF-2009-K20601000004-09E0100-00410) supported by PNU-IFAM JRC
文摘Powder extrusion, which is based on the superplastic behavior of Zn-22%A1 eutectoid alloy, was proposed to reduce the forming load and promises to provide fine microstructures in the manufacture of miniature helical gears. The specifications of the helical gears were as follows： module, 0.3; number of teeth, 12; and helix angle, 15°. Compacted powders were consolidated by sintering and solution heat treatment. The consolidated billets consisted of lamellar and fine-grained microstructures. Extrusion experiments were carried out under the following conditions： temperature, 250 ℃; strain rates, 2.36× 10-3 s^-1 and 1.18× 10^-1 s-1. The mechanical properties of the extruded helical gears were investigated by measurement of the Vickers hardness and extrusion load, and by scanning electron microscopy.
基金sponsored by China Postdoctoral Science Foundation (20080430668)
文摘Numerical simulation was performed in an atomizing chamber to investigate the movements and thermal states of the atomized metal droplets in the spray forming process. The velocity, temperature and solid fractions of metal droplets with different diameters and under different atomizing pressures were investigated. The results indicate that a higher atomizing pressure results in the increased flying velocity of the metal droplets and a decrease in the cone-shaped angle formed by their flight paths. Synchronously, the cooling of the metal droplets is accelerated and the time of the complete solidification process is shortened. Under the same atomization pressure, large metal droplets have a lower flying speed and a lower rate of temperature decrease in the atomizing chamber than small metal droplets. In addition, metal droplets flying along the edge of the atomizing region cool faster than those flying in the core region.
文摘Water atomized Fe Ni Mo steel powder, was utilized as base powder for designing powder mixtures for warm pressing. The warm pressing and sintering behaviours of the powder mixtures were studied. The results show that, compared with the pressing at room temperature, the green density gain by warm pressing is within a range of 0.10 0.19 g/cm 3 and reduction in spring back is 30% 40% of the ambient, and maximum green density of 7.32 g/cm 3 at 735 MPa is obtained as the graphite mass fraction is 0.8%. It was found that sintered densities of the compacts were reduced slightly due to releasing of elastic stress stored in the compacts during sintering. The warm pressing of steel powders gives evidence for substituting the traditional double pressing and double sintering process.
文摘Objective: As a Chinese drugs preparation to clear heat and remove toxicity, Shuanghuanglian (SHL) has been widely used, but the clinical efficacy and safety of SHL on chronic pharyngitis remain unclear, especially the application of atomized inhalation of SHL need to be verified. The aim of this study was to evaluate its clinical efficacy and safety for chronic pharyngitis. Methods: From the Cochrane Library, Pubmed, EMbase, Wanfang Datebase, CNKI (China National Knowledge Infrastructure), VIP (Chinese Scientifc Journals Database), CBM (Chinese Biomedicine Database), We got the qualified randomized controlled trials(RCTs) and adopted RevMan5.3 software and the risk of bias tool according to the Cochrane to perform a metaanalysis. Results: Ten RCTs, a total of 950 cases (involving 472 cases in SHL group and 478 in control group) were included. The results showed that the clinical efficacy in SHL group was superior to control group [Chi2=5.61, 95%CI (4.29, 11.43), P<0.05], and four literatures reported no obvious adverse reactions in SHL group. Conclusion: Application of atomized inhalation of SHL may have a potential advantage in treating chronic pharyngitis. However, due to the limitation of the quality and sample size of those studies, the accuracy of the result should be treated with caution, higher standardized researches are required to justify the conclusion.
基金The authors gratefully acknowledge the financial support from the National Natural Science Foundation （NNSF） of China and the International Cooperation Key Project of NNSF of China （Nos. 50395104, 50271076 and 50371092）the Natural Science Foundation of Liaoning Province （20050047）.
文摘Modeling and simulation have been carried out for Al-Pb alloys to investigate the Brownian coagulation effect on the microstructure development in a gas-atomized drop during the liquid-liquid decomposition. The results indicate that Brownian coagulation has a weak effect on the nucleation and a relatively strong effect on coarsening the minority phase droplets. The influence of Brownian coagulation on the liquid-liquid decomposition decreases with the increase in the diameter （or the decrease in the cooling rate） of the atomized drop.
基金Project(CXZZ20140506150310438) supported by the Science and Technology Program of Shenzhen,ChinaProject(2017GK2261) supported by the Science and Technology Program of Hunan Province,China
文摘Gas-atomized pure metal or alloy powders are widely used as raw material in the preparation of high performance materials by powder metallurgy route（compaction and sintering）. However, cold compactibility of gas-atomized Al-Si alloy powder is inhibited due to the high strength as a result of the refined Si phases and the supersaturated Al matrix. The effect of annealing on improving the compactibility of Al-Si alloy powder was studied. The densification was investigated by the HECKEL compaction equation in terms of deformation capacity. Moreover, the microstructures and bending fracture surfaces of the green compacts were examined to clarify the densification behavior. The results show that a maximum relative density of 96.1% is obtained when the powder is annealed at 400 °C. The deformation capacity is significantly improved by annealing treatment due to the softening of Al matrix, precipitation of supersaturated Si phases, dissolution of needle-like eutectic phase, and spheroidization of Si phases.
基金Item Sponsored by National Natural Science Foundation of China (50701030)National Basic Research Program of China(2010CB630802)
文摘The microstructural evolution of the gas atomized Fe-25Cr-3.2C powders was investigated by using optical microscope, scanning electron microscope, and X-ray diffraction. The experimental results showed that the atomized Fe-25Cr-3.2C powders were mainly composed of austenite and （Fe,Cr）7 C3 carbide. Eutectic microstructure was developed in the larger particles, whereas dendritic microstrueture was obtained in the particles with diameter less than 38 μm. The reason for microstructure change should be the difference of nucleation undercooling for particles.
基金supported by Science and Technology Commission of Shanghai Municipality of China(No.09ZR1421200)Shanghai Maritime University of China(No.2008462)
文摘Effects of discharge mode, voltage applied, size of the nozzle discharge electrode and flow rate of water on the generation of hydroxyl radical were investigated in air discharge with atomized water, by using optical emission spectroscopy （OES）. Water was injected into the discharge region through the discharge nozzle electrode, and a large amount of fine water drops, formed and distributed in the discharge region, corona discharge was more effective to generate were observed. It was found that negative DC the hydroxyl radicals in comparison to positive DC corona discharge or negative pulsed discharge. A larger outer diameter of the nozzle electrode or a stronger electric field is beneficial for hydroxyl-radical generation. Moreover, there is a critical value in the flow rate of atomized water against the discharge voltage. Below this critical value, hydroxyl-radical generation increases with the increase in flow rate of the water, while above this value, it decreases. In addition, it is observed that OES from the discharge is mainly in the ultraviolet domain. The results are helpful in the study of the mechanism and application of plasma in pollution-control in either air or water.
基金financial support from MINECO through NEXMAG(M-era.Net,PCIN-2015-126)and 3D-MAGNETOH(MAT2017-89960-R)projectsfrom the Regional Government of Madrid through the NANOMAGCOST(P2018/NMT-4321)projectIMDEA Nanociencia is supported by the"Severo Ochoa"Programme for Centres of Excellence in R&D,MINECO(SEV-2016-0686).
文摘An unprecedentedly short milling time of 30 s was applied to gas-atomized MnAl powder in order to develop permanent magnet properties and,in particular,coercivity.It is shown that such a short processing time followed by annealing results in efficient nanostructuring and controlled phase transformation.The defects resulting from the microstrain induced during milling,together with the creation of the bphase during post-annealing,act as pinning centers resulting in an enhanced coercivity.This study shows the importance of finding a balance between the formation of the ferromagnetic s-MnAl phase and the bphase in order to establish a compromise between magnetization and coercivity.A coercivity as high as 4.2 kOe(1 Oe=79.6 A·m^-1)was obtained after milling(30 s)and annealing,which is comparable to values previously reported in the literature for milling times exceeding 20 h.This reduction of the postannealing temperature by 75℃ for the as-milled powder and a 2.5-fold increase in coercivity,while maintaining practically unchanged the remanence of the annealed gas-atomized material,opens a new path for the synthesis of isotropic MnAl-based powder.
文摘The fine structure of hydrogen storage alloy powders MiNi4.3-xCoxMr0.4AI0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis method. Two sets of CaCu5-type crystal constants were observed in the studied alloys and one set was larger than the other. With decreasing powder radius the solidification rate of powder increased, and so did the percentage of a particle part with larger crystal constants. The reason why there were two sets of crystal constants might be the difference of solidification rate between the outside and inside of a particle.
基金supported by the following foundation items:the National Natural Science Foundation of China(Nos.52375447 and 52205481)the Shandong Provincial Natural Science Foundation of General Program(No.ZR2024ME205)+1 种基金the Special Fund of Taishan Scholars Project(No.tsqn202408220)the Shandong Provincial Natural Science Foundation of Youth Fund(No.ZR2021QE116).
文摘In the precision cutting of difficult-to-process metals,surface thermal damage to a workpiece is a significant technical challenge.Although clean minimum quantity lubrication(MQL)technology,which replaces traditional pouring cooling,is used,inadequate heat dissipation remains an issue.Cryogenic air MQL(CAMQL),an eco-friendly technology,can enhance the heat transfer performance of the lubricating film in the cutting zone,offering excellent cooling and lubrication effects.However,the influence of jet and temperature parameters on the average particle size and distribution characteristics of atomized droplets is not well understood.This study first analyzes the evolution of lubricant physical properties and establishes a quantitative mapping relationship between cryogenic air temperature and physical parameters of lubricant.Next,the unstable fluctuation in the annular liquid film at the two-phase flow nozzle exit is observed and analyzed.A thickness model of annular liquid film is developed,revealing the effect of airflow field on the annular liquid film.Finally,a model for the average particle size of atomized droplets under CAMQL is established.Numerical analysis and validation experiments under different working conditions show that the measured values align with the theoretical values.Under an air pressure of 0.4 MPa and an air flow temperature of−50℃,the droplet particle size is 133.5μm,with an error of 8.2%.The effect of air pressure on particle size is greater than that of air flow temperature.Additionally,the distribution spans of droplet size under different conditions are analyzed,and the results demonstrated that low temperatures help shorten the interval between particle sizes and improve the relative uniformity of particle size distribution.This research provides a theoretical basis for the application of CAMQL technology in the cutting process.
基金the National Natural Science Foundation of China (Grant No. 50539060).
文摘In this article, the unified mathematical model for splash droplets and suspended mist of atomized flow was established, which classifies the atomized sources into the splash source and the suspended source. For the splash source, the Lagrangian method was used to simulate the random motion of splash water droplets, and for the suspended source the theory of air-water two-phase flow was used to simulate the mist flow moving in particle clouds. The rainfall intensity of the atomized flow was obtained by summarizing the rainfall intensities relative to the above two types of atomized sources. Both experimental data and prototype observation data were used for the verification of the mathematical model. For both the distribution of rainfall intensity, and the outer edge of the atomized flow, the simulation results are in agreement with the experimental data or prototype observation data.
基金Project Supported by the National Nature Science Foundation of China (Grant Nos: 50279033, 50539060)
文摘Atomized flow is an unnatural two-phase flow produced while water discharges in water release structures. This flow might threaten the normal operation of hydraulic and hydroelectric installations owing to the unnatural and high-density rain as well as the unnatural and dirty mist. The splash region, the region with the highest rain intensity, hence should receive much attention during the design and operation of the hydraulic and hydroelectric installations. In this paper rain intensity distribution in the splash region of the atomized flow is investigated experimentally, and the method of random simulation is used to predict the rain intensity distribution in the splash region.
文摘Slit type bucket is one kind of flip bucket for energy dissipation generally used in the hydraulic project. In this paper the atomized flow produced behind this energy dis sipator is analyzed, a numerical model for the aerated jet con sidering air entrainment and air resistance force is suggested, and simulation of the rain resulted by the atomized flow is also discussed. Furthermore, the prototype observation data for the atomized flow of Dongjiang Hydropower Station is used to verify the model suggested.
