Simulation and experimental study on temperature field of fluid jet-dispenser
Fluid jet-dispensing technology has been widely used in micro-electronic encapsulation industry. The fluid viscosity varies as temperature changes, while it affects the process remarkably. Besides basic method on temperature field solution, some thermal behaviors, including heat conduction and heat exchange, boundary conditions and some physical parameters are overall analyzed in this paper. Based on the simulation software platform ANSYS, a two-dimensional transient temperature field model of jet-dispenser was built, and simulation programs on temperature field for two sorts of fluid with obviously different thermal conductivity were performed. Then heating experiments were finished to validate the feasibility of FEA, and results show that temperature distribution is homogeneous along fluid area and it meets the conditions of jetting.
Study on temperature field of fluid jet-dispenser based on two piezoelectric stacks
Fluid jet-dispenser based on two piezoelectric stacks can achieve high frequency, micro injection. Each sort of fluid has its own viscosity, which varies with temperature remarkably. Heating device was designed in order to reduce the viscosity of fluid, so the applicable scope of fluid and the stability of dispensing will be improved evidently. Based on the simulation software platform COMSOL, a three-dimensional transient temperature field model of jetting dispenser was built, in which a temperature feedback was set and the difference of two heating modes in channel was analyzed. The temperature was measured in real time in the experiment. The results showed that: the system can achieve the temperature equilibrium in 130s and the heating device system was feasible, which can achieve channel temperature stability.
Silica in Soils1
Publisher Summary Silica in free and combined forms is a dominant component of the solid material of many soils, and dissolved silica is commonly a major solute of soil solutions. Breakdown of primary silicates, translocation of silica in solution, and deposition of secondary silica-containing substances are involved in the development of soils. Ions essential for the growth of plants are released to the soil solution as silicates weather, and these ions may be held against leaching at exchange sites on other silicates. Silica is absorbed in appreciable quantities by some plants and is returned to the surface of the soil as the plants decay. The nature and transformations of silica and silicates in soil are, thus, fundamental to an understanding of many aspects of soil and plant sciences.