A device which cools a discharge electrode to cause condensation and then electrostatically atomize the condensed moisture by applying high voltage to the discharge electrode has been developed. The electrostatic particulate water generated through the electrostatic atomization by this device has been confirmed to have a peak particle diameter of approximately 20 nm. In addition, simultaneous formation of radicals was verified by ESR analysis. It has been confirmed that this electrostatic particulate water has the effects of deodorization by adsorbing/absorbing odors and deactivation of pollen or mite antigens. An air cleaner equipped with this electrostatic atomization device has been developed. Further, when this device was employed on a hair dryer, it was found to have the effects of increasing the moisture-holding power of hair, giving hair softness and increasing the tensile breaking strength of hair. This is presumed to be due to the abundant moisture given to hair compared to negative ion devices.
Cryogenic aerosol cleaning is a very unique technology that cleans without the use of chemicals and de-ionized water. With optimization of recipe parameters, this technology will provide solutions for the significant problems or difficulties in new materials, e.g., high-k or metal gate, fragile porous low-k, sensitive gate pattern for 65 nm node, in which the conventional wet cleaning may not meet the requirements. As the technology node goes on for 45 nm node beyond, cryogenic aerosol technology will be required to be implemented for advanced production line.
Miniaturization, cost reduction and higher performance in RF wireless communication products are demanded for constructing a ubiquitous computing network system. To fulfill these demands, we propose an organic built-up circuit board with various embedded passive ceramic component films for the next-generation RF modules. In the circuit board we propose, ceramic films have to be built-up on a resin substrate at a temperature lower than the endurance temperature of the resin. Our novel aerosol deposition (ASD) method through the use of accelerated ceramic nano-particle bombardment is therefore one of the most effective deposition methods for the ceramic film. We describe a novel ASD approach to fabricate embedded capacitors on organic flame retardant type 4 (FR-4) substrates and the correlation between the microstructure and dielectric properties of ASD dielectric films deposited under various conditions. We also confirmed the formation of dense BaTiO3 dielectric films on organic substrates at room temperature. Embedded capacitors on an FR-4 substrate, fabricated as a prototype with this ASD film, had a capacitance density of 300 nF/cm2.
We developed functional oxide films with a large electro-optic (EO) effect for use in very small, low-power EO conversion devices. We have applied an aerosol deposition (AD) to form lead oxide films with a perovskite structure. (Pb, La) (Zr,Ti) O3 films were deposited and systematically studied in terms of optical and EO properties. Transparent films with a large EO effect, which have acceptable transmittance loss level for use as optical devices, were obtained. In this report, we summarize recent progress and future prospects on AD for optical devices application.
This paper introduces dry film fabrication systems, i.e., Gas Deposition (GD) system and Aerosol Gas Deposition (AGD) system, and their applied fields. Nanoparticles of inorganic materials can be formed by the gas evaporation method (the gas condensation method) . In gas deposition method, particles formed by the gas evaporation method in an evaporation chamber are transported to another chamber (a deposition chamber) through a transfer pipe. Particles are accelerated in the pipe with a gas flow and ejected through a nozzle to form a film in the deposition chamber which is evacuated at a pressure lower than 1 kPa. With the aerosol gas deposition method, particles formed elsewhere are dispersed into a gas flow and ejected through a wide nozzle to form films. Ceramics particles are deposited on a substrate, forming a high density film with a strong adhesion under a room temperature condition.
SPM and CO concentrations are low during the day time because the atmosphere is well mixed. In summer, solar radiation is twice as high as that in winter. So the atmospheric mixing during the day is stronger in summer than winter. However, in Kyoto, SPM and CO concentrations are not low in summer compared to winter. In order to reveal the reasons of these diurnal concentration variations, we estimated SPM and CO background concentrations using the data of the Atmospheric Environmental Regional Observation System in Kyoto. We conclude that SPM and CO diurnal concentration variations are caused by the following reasons; (a) SPM or CO concentrations decrease to SPM or CO background concentrations and (b) SPM background concentration is the highest in summer and is the lowest in winter and CO background concentration is almost constant through all seasons.
A moment method of the log-normal distribution is applied to evaporation of particles by introducing correction factors calculated from the error function. In the free-molecular regime, the improved moment method is tested for the evaporation and the sensitivity to time-integration scheme is examined. For the forward and backward Euler solutions, small time step size (<1 s for dv/dt = -10-10v2/3, where v is the particle volume and t is time) is required to accurately simulate the evaporation, since the difference from the exact one becomes larger with increasing the time step size. For large time step size (∼10 s) , the fourth order Runge-Kutta and simple exponential solutions agree well with the exact solution of the evaporation in the free molecular regime.
We have developed a large annular-type differential mobility analyzer (DMA) , having outer electrode diameter of 100 mm to increase the sampling flow rate of size-classified aerosols up to 30 L/min. In order to calibrate this new DMA, three types of monodisperse polystyrene latex (PSL) particles with nominal diameter ranging from 28 to 100 nm were used as standard particles. PSL particles suspended in distilled water were aerosolized by a nebulizer and then introduced into the DMA. The mean diameters and standard deviations of these PSL particles were calculated by Ehara's method (Ehara, K. et al., Aerosol Sci. Technol., 32, 434-452 (2000) ) and compared with their nominal diameters and uncertainties. Nominal and measured diameters are in good agreement. These resutls indicate that this DMA is useful to classify large volume of nanometer-sized aerosols and for further measurements such as chemical analysis of particulate materials or inhalation experiments.