A new approach to explain forest interception was proposed by introducing micro-droplets of crushed raindrops during rainfall. The aerodynamic diffusion and transfer of both vapour and micro-droplets from canopy to up...A new approach to explain forest interception was proposed by introducing micro-droplets of crushed raindrops during rainfall. The aerodynamic diffusion and transfer of both vapour and micro-droplets from canopy to upper air were described and calculated, and proposed formulas applied to eight rainfall events at the Okunoi Experimental Station, Tokushima, Japan. Contributions from droplet transfer were 0.9-58.2 times of contributions from vapour transfer, taking a majority portion in total interception loss. Accounting only the vapour transfer or evaporation loss as estimated by Penman equation was not able to account for actual interception loss. The micro-droplet flux component took major portion in the two heavily rained events, and completely made up the interception as happened in October 2004. The droplet flux could accommodate a high interception rate, even when the air was nearly vapour-saturated and vapour flux was zero. This approach provided a new explanation to extraordinarily high interception rates.展开更多
The experiments were conducted to focus on the desulfurization and evaporation characteristics of lime slurry droplets at 298-383 K. We designed an evaporation-reaction chamber with quartz glass windows.The monodisper...The experiments were conducted to focus on the desulfurization and evaporation characteristics of lime slurry droplets at 298-383 K. We designed an evaporation-reaction chamber with quartz glass windows.The monodisperse slurry droplet stream was injected into the evaporation reaction chamber, and the inlet gas components(air, air + SO_(2)) were introduced into the chamber. We applied the magnified digital in-line holography to measure the droplet parameters and calculated the evaporation rate. The effects of temperature, droplet concentration, and SO_(2) concentration on the evaporation rate of Ca(OH)_(2) droplets were discussed. Moreover, the Ca(OH)_(2) droplets under different experimental conditions were sampled,and the droplets were observed and analyzed using an off-line microscope. The evaporation rate of the Ca(OH)_(2) droplet increased at first, and then decreased during the falling process, and remained constant at last. The average evaporation rate of the Ca(OH)_(2) droplets increased significantly with the temperature increasing.展开更多
The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an ...The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an instant manner and a slow manner, respectively; the field strength is linear increased. With instantly raising the field, it is observed that the ferrofluid layer is split into several regularly distributed micro-droplets, and that the number of micro-droplets is linear to the magnetic field strength and the thickness of the liquid layers. When the field is slowly increased, a liquid ring together with several micro-droplets appears from the ferrofluid layer splitting. A spatial drift of the micro-droplets is also observed in the process of increasing the magnetic field. Our results are useful for manipulating the splitting regularities of ferrofluid layers by magnetic field, which may be used in non-contact segmentation, and magnetically manipulated drug carriers for targeting the therapy, etc.展开更多
Many liquid metals have a high boiling point,strong electrical conductivity,high thermal conductivity,and nontoxic properties,which make them ideal targets for applications in different fields such as optics,microcir...Many liquid metals have a high boiling point,strong electrical conductivity,high thermal conductivity,and nontoxic properties,which make them ideal targets for applications in different fields such as optics,microcircuits,electronic switches,micro-electromechanical System(MEMS)devices and 3D printing manufacturing.However,owing to the generally high surface tension of these liquids,achieving uniform micro-droplets is often a challenge due to the inherent difficulties in controlling their size and shape.In this study,a gallium indium alloy(GaIn24.5)has been used in combination with a pneumatic drop-on-demand(DOD)injection technology to carry out a series of experiments.The micro-droplet forming process has been explored for different pressure and pulse width conditions.Uniform metal droplets(diameter 1080μm)have been obtained with a 1.5 kPa jet pressure,100 ms pulse width,and 50%duty ratio.The standard deviation of the measured metal droplets diameter has been found to be approximately 20μm.展开更多
Micro-droplet jetting belongs to the field of precision fluid dispensing techniques.Unlike traditional subtraction manufacture process,micro-droplet jetting as an additive fabrication technique with features of non-co...Micro-droplet jetting belongs to the field of precision fluid dispensing techniques.Unlike traditional subtraction manufacture process,micro-droplet jetting as an additive fabrication technique with features of non-contact and data-driven represents a new development trend of modern manufacturing process.In this paper,the design,fabrication and performance of a multi-materials drop-on-demand (DOD) inkjet system based on pneumatic diaphragm actuator were described.For capturing the droplet ejection process and measuring the droplet dimension,a self-made in situ imaging system based on time delayed external trigger was set up.The performance of the generator was studied by adjusting the structure and control parameters.Furthermore,the influence of fluid properties on the droplet ejection process was experimentally investigated.Micro-solderballs of 160.5 μm in diameter and UV curing adhesive micro-bumps of 346.94 μm in contact diameter with the substrate were produced.The results demonstrated that the DOD inkjet generator possesses characteristics of robust,easy to operate and maintain,and able to withstand high temperature as well as applicability to a wide variety of materials including polymers,low melting point resin and high melting point metal.The system has a great potential of being used in the fields of IC and MEMS packaging,3D printing,organic semiconductor fabrication,and biological and chemical analysis.展开更多
文摘A new approach to explain forest interception was proposed by introducing micro-droplets of crushed raindrops during rainfall. The aerodynamic diffusion and transfer of both vapour and micro-droplets from canopy to upper air were described and calculated, and proposed formulas applied to eight rainfall events at the Okunoi Experimental Station, Tokushima, Japan. Contributions from droplet transfer were 0.9-58.2 times of contributions from vapour transfer, taking a majority portion in total interception loss. Accounting only the vapour transfer or evaporation loss as estimated by Penman equation was not able to account for actual interception loss. The micro-droplet flux component took major portion in the two heavily rained events, and completely made up the interception as happened in October 2004. The droplet flux could accommodate a high interception rate, even when the air was nearly vapour-saturated and vapour flux was zero. This approach provided a new explanation to extraordinarily high interception rates.
基金supported by the National Natural Science Fund for Distinguished Young Scholars (No. 51825605)。
文摘The experiments were conducted to focus on the desulfurization and evaporation characteristics of lime slurry droplets at 298-383 K. We designed an evaporation-reaction chamber with quartz glass windows.The monodisperse slurry droplet stream was injected into the evaporation reaction chamber, and the inlet gas components(air, air + SO_(2)) were introduced into the chamber. We applied the magnified digital in-line holography to measure the droplet parameters and calculated the evaporation rate. The effects of temperature, droplet concentration, and SO_(2) concentration on the evaporation rate of Ca(OH)_(2) droplets were discussed. Moreover, the Ca(OH)_(2) droplets under different experimental conditions were sampled,and the droplets were observed and analyzed using an off-line microscope. The evaporation rate of the Ca(OH)_(2) droplet increased at first, and then decreased during the falling process, and remained constant at last. The average evaporation rate of the Ca(OH)_(2) droplets increased significantly with the temperature increasing.
基金Funded by the National Natural Science Foundation of China(No.51077006)
文摘The regular distribution of micro-droplets splitting from thin ferrofluid layer is systematic experimentally investigated, as the layer is placed in a vertical magnetic field. In this work, the field is applied in an instant manner and a slow manner, respectively; the field strength is linear increased. With instantly raising the field, it is observed that the ferrofluid layer is split into several regularly distributed micro-droplets, and that the number of micro-droplets is linear to the magnetic field strength and the thickness of the liquid layers. When the field is slowly increased, a liquid ring together with several micro-droplets appears from the ferrofluid layer splitting. A spatial drift of the micro-droplets is also observed in the process of increasing the magnetic field. Our results are useful for manipulating the splitting regularities of ferrofluid layers by magnetic field, which may be used in non-contact segmentation, and magnetically manipulated drug carriers for targeting the therapy, etc.
基金the National Natural Science Foundation of China(Grant Nos.51305128 and 52005059)the China Postdoctoral Science Foundation(Grant No.2020M673127)+5 种基金the Natural Science Foundation of Chongqing(Grant No.cstc2020jcyj-bshX0008)the Fundamental Research Funds for the Central Universities of China(Grant No.2020CDJQYA035)the key scientific and technological project of Henan province(Grant No.192102210055)the“Construction of double city economic circle in Chengdu Chongqing area”scientific and technological innovation project(Grant No.KJCXZD2020011)the key scientific research projects of the colleges and universities of Henan province(Grant No.18A4600050)Outstanding Young Backbone Teachers projects of Xuchang University.
文摘Many liquid metals have a high boiling point,strong electrical conductivity,high thermal conductivity,and nontoxic properties,which make them ideal targets for applications in different fields such as optics,microcircuits,electronic switches,micro-electromechanical System(MEMS)devices and 3D printing manufacturing.However,owing to the generally high surface tension of these liquids,achieving uniform micro-droplets is often a challenge due to the inherent difficulties in controlling their size and shape.In this study,a gallium indium alloy(GaIn24.5)has been used in combination with a pneumatic drop-on-demand(DOD)injection technology to carry out a series of experiments.The micro-droplet forming process has been explored for different pressure and pulse width conditions.Uniform metal droplets(diameter 1080μm)have been obtained with a 1.5 kPa jet pressure,100 ms pulse width,and 50%duty ratio.The standard deviation of the measured metal droplets diameter has been found to be approximately 20μm.
基金supported by the National Natural Science Foundation of China (Grant No. 50775087)
文摘Micro-droplet jetting belongs to the field of precision fluid dispensing techniques.Unlike traditional subtraction manufacture process,micro-droplet jetting as an additive fabrication technique with features of non-contact and data-driven represents a new development trend of modern manufacturing process.In this paper,the design,fabrication and performance of a multi-materials drop-on-demand (DOD) inkjet system based on pneumatic diaphragm actuator were described.For capturing the droplet ejection process and measuring the droplet dimension,a self-made in situ imaging system based on time delayed external trigger was set up.The performance of the generator was studied by adjusting the structure and control parameters.Furthermore,the influence of fluid properties on the droplet ejection process was experimentally investigated.Micro-solderballs of 160.5 μm in diameter and UV curing adhesive micro-bumps of 346.94 μm in contact diameter with the substrate were produced.The results demonstrated that the DOD inkjet generator possesses characteristics of robust,easy to operate and maintain,and able to withstand high temperature as well as applicability to a wide variety of materials including polymers,low melting point resin and high melting point metal.The system has a great potential of being used in the fields of IC and MEMS packaging,3D printing,organic semiconductor fabrication,and biological and chemical analysis.
基金partially supported by the Key Project of National Natural Science Foundation of China (91748206)Dean’s Research Funding and the Frontier Project of the Chinese Academy of Sciences
