• Korean Journal of Materials Research
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• v.12 no.7
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• pp.555-559
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• 2002

Blue-emitting $Sr_{10}$($PO$)$_{6}$ $Cl_2$:$Eu^{2+}$ and $_{(Sr,Mg) }$ 10/($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ phosphor particles for application of long-wavelength UV LED were prepared by ultrasonic spray pyrolysis. The luminescence characteristics under long- wave-length ultraviolet of the $Sr_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ and (Sr,Mg)$_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$^Eu{2+}$ phosphor particles prepared by the spray pyrolysis were compared with that of the commercial product. The PL intensity of the $Sr_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ particles prepared by the spray pyrolysis was lower than that of the commercial $Sr_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ particles because prepared $Sr_{10}$ ($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ phosphor particles had porous structure and hollow morphology. However, the PL intensity of the (Sr,Mg)$_{10}$($PO_4$)$_{6}$ $Cl_2$:$Eu^{2+}$ phosphor particles prepared by the spray pyrolysis was 8% higher than that of the commercial one. The high brightness of $(Sr,Mg)_{10}$ ($PO_4$)$_{6}$ $Cl_2$:Eu$^{2+}$ phosphor particles prepared by spray pyrolysis is due to the dense structure and high crystallinity of particles. The TEX>$(Sr,Mg)<_{10}$ ($PO_4$)$_{6}$ /$Cl_2$:$Eu^{ 2+}$ phosphor particles had main emission peak t 448 nm under long- wavelength ultraviolet.

• Journal of ILASS-Korea
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• v.11 no.4
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• pp.251-265
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• 2006

To prevent the ozonosphere from being destroyed by Halon, it is an urgent task to find out Halon replacement. As one of the replacements water mist have showed broad applications by its advantages: little pollution to environment (not destroying the ozone layer or bring green house effect), extinguishing fire quickly, consuming a small quantity of water and having little damage to the protected objects. The methods of generating water mist strongly influence fire suppression effectiveness, which determine the cone angle, drop size distribution, flux uniformity, and momentum of the generating spray. The traditional water mist nozzle included pressure jet nozzles, impingement nozzles and twin-fluid nozzles. All of them have more or less disadvantages for fire suppression. Therefore, many research institutes and corporations are taking up with innovations in mist generation. This article provided some recent studies in State Key Laboratory of Fire Science (SKLFS) of University of Science and Technology of China. SKLFS have investigated new methods of generating water mist (i.e. effervescent atomization and ultrasonic atomization). and self developed a series of nozzles and developed advanced DPIVS (Digital Particle Image Velocimetry and Sizing) technique. Characteristics of water mist (the distribution of droplet sizes, flux density, spray dynamics and cone angle) produced by these nozzles were measured under different conditions (work pressure, nozzle geometry, etc.) using LDV/APV and DPTVS systems. A series of experiments were performed to study the fire suppression effectiveness in different fire scenario (different kindsof the fuel, fire size and ventilation conditions). The fire extinguishing mechanisms of water mist was also discussed.

• Journal of Powder Materials
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• v.17 no.4
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• pp.263-269
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• 2010

Hexagonal barium ferrite ($BaFe_{12}O_{19}$) nano-particles have been successfully fabricated by spraypylorysis process. $BaFe_{12}O_{19}$ precursor solutions were synthesized by self-assembly method. Diethyleneamine (DEA) surfactant was used to fabricate the micelle structure of Ba-DEA complex under various DEA concentrations. $BaFe_{12}O_{19}$ powders were synthesized with addition of Fe ions to Ba-DEA complex and then fabricated $BaFe_{12}O_{19}$ powders by spray-pyrolysis process at the temperature range of $800{\sim}1000^{\circ}C$. The molar ratio of Ba/DEA and heat-treatment temperatures significantly affected the magnetic properties and morphology of $BaFe_{12}O_{19}$ powders. $BaFe_{12}O_{19}$ powders synthesized with Ba/DEA molar ratio of 1 and heat-treated at $900^{\circ}C$ showed the coercive forces (iHc) of 4.2 kOe with average crystal size of about 100 nm.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.303-308
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• 2013

A remote controlled sprayer has designed, manufactured and experimented to spray well on pear trees with pesticides. This study was executed to automate pest management of pear trees. Types of spray nozzle, which was used on the system, were analyzed experimentally to find an optimal spray equipment configuration with several nozzles. Attributions of ultrasonic sensors were analyzed to adjust spraying distance of an unmanned sprayer system. This paper investigated shapes of pear trees and cultivating environment of pear orchard. In order to select optimal spray environment, liquid distribution was measured while angle of nozzle was changed. Additionally, liquid distribution by distance and sprayed liquid capacity by side distance were measured. According to information of shapes of pear trees and cultivating environment of pear orchard, sprayer frames of an unmanned sprayer system were manufactured and sprayer frames were suitable for interval of pear trees. The sprayer system could adjust width of sprayer frames to 2.5 m and height of sprayer frames to 1.7 m. Optimal angle of nozzle, and optimal distance between objects and nozzle were $15^{\circ}$ and 0.8 m. When side distance was placed from 1.2 m to 1.8 m, sprayed capacity reached to the highest amount.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.80-84
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• 2005

Nano-sized $Y_2O_3:Eu$ phosphor particles were prepared by ultrasonic spray pyrolysis. The effect of polymeric precursor and lithium carbonate flux on the morphology and luminescence characteristics of nano-sized $Y_2O_3:Eu$ phosphor particles was investigated. When using the spray solution containing both the polymeric precursor and the flux, the $Y_2O_3:Eu$ particles with spherical shape and micron size were turned into nano-sized $Y_2O_3:Eu$ phosphor particles during the post-treatment at high temperature. The mean size of $Y_2O_3:Eu$ phosphor particles was affected by the contents of polymeric precursors and lithium carbonate flux, and preparation temperature. The as-prepared particles by spray pyrolysis at high temperature from solution containing high contents of polymeric precursors had good photoluminescence intensity under vacuum ultraviolet after post-treatment above $1,000^{\circ}C$. The prepared nano-sized $Y_2O_3:Eu$ phosphor particles had comparable photoluminescence intensity under vacuum ultraviolet light with that of the commercial $Y_2O_3:Eu$ phosphor particles prepared by solid state reaction method.

• Journal of the Korean Ceramic Society
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• v.36 no.11
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• pp.1205-1210
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• 1999

Ceria based electrolytes were fabricated by a plasma spraying method. The porosity which was crated during the plasma spraying process was infiltrated with Ce0.8Gd0.2O2 sol by ultrasonic treatment and heat treatment at 90$0^{\circ}C$ in order to improve physical and electrical properties. The porosity decreased from 9.8% to 6.5% and gas permeability at 80$0^{\circ}C$ decreased from 16.7$\times$10-3 to 5.7$\times$10-3 cm3(STP)/cm2.s.cmHg as the number of treatment increased 10 cycles. The ionic conductivity was also increased about 30% after 10 times of sealing.

• Journal of the Korean Ceramic Society
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• v.35 no.6
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• pp.529-534
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• 1998

Agglomeration-free indium oxide particles were produced by ultrasonic pyrolysis of indium nitrate(3 hy-drate) solution. Th mean size of particles was increased from 3 $\mu\textrm{m}$ to 11$\mu\textrm{m}$ with increasing intial con-centrations of indium nitrate from 0.05mol% to 4.83 mol% When the input rate of indium nitrate solution was increased from 0.1 cm3/min to 0.8cm3/min the size of particles remained same and only the pro-duction rate of particles was increased. At 300$^{\circ}C$ the particles were white color with low crystallinity. But the color turned into yellow with increasing reaction temperature. The change of particle size was not ob-served with increasing temperatuer up to 700$^{\circ}C$ IR spectrum and TGA analysis confirmed that the purity of indium oxide was increased with temperature of reaction.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.84-88
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• 2009

Al doped $LiMn_2O_4$ cathode powders with fine size were synthesized by an ultrasonic spray pyrolysis method from the spray solution with citric acid and ethylene glycol. The as-prepared powders with spherical shape, porous structure and micron size turned into $LiMn_{11/6}Al_{1/6}O_4$ powders with micron size and regular morphology after post-treatment above $800^{\circ}C$. The $LiMn_{11/6}Al_{1/6}O_4$ powders had low initial discharge capacity of 94 mAh/g at a post-treatment temperature of $700^{\circ}C$. As the post-temperature increased from $750^{\circ}C$ to $1,000^{\circ}C$, the initial discharge capacities of the $LiMn_{11/6}Al_{1/6}O_4$ powders changed from 103 to 117 mAh/g. The $LiMn_{11/6}Al_{1/6}O_4$ powders had the maximum discharge capacity at a post-treatment temperature of $750^{\circ}C$. However, the $LiMn_{11/6}Al_{1/6}O_4$ powders post-treated at a temperature of $900^{\circ}C$ had the good cycle properties. The discharge capacities of the $LiMn_{11/6}Al_{1/6}O_4$ powders dropped from 107 to 100 mAh/g (93% capacity retention) by the 70th cycle at a current density of 0.1 C.

• Journal of Conservation Science
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• v.28 no.3
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• pp.285-296
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• 2012

This study was to assess the effect of consolidation for intension measures of stone cultural heritage using artificially weathered stones. We have prepared four kinds of stones (Gyeongju Namsan Granite, Iksan Granite, Yeongyang Sandstone, Jeongseon Marble), and manufactured fresh, weathered and highly weathered stone samples by thermal shock for each rock type. The samples were treated with three consolidants (Wacker OH 100, Remmers KSE 300, 1T1G) by three methods {immersion, capillary rise (partial immersion), spray}, and tested for weight, porosity, ultrasonic velocity, Equotip hardness and color before and after treatment. As a result, the effect of consolidation was widely influenced by porosity and treatment methods. Wacker OH 100 was shown the highest consolidation effect in almost every stone sample.

• Journal of Sensor Science and Technology
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• v.6 no.2
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• pp.155-162
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• 1997

Zinc oxide(ZnO) thin films were deposited on r-plane sapphires from a solution containing zinc acetate. The films were obtained in a hot wall reactor by the pyrolysis of an aerosol produced by an ultrasonic generator. The crystallinity, surface morphology and composition of the films have been studied using the x-ray diffraction method(XRD) scanning electron microscopy(SEM) and Auger electron spectroscopy (AES) respectively. The influences of the substrate temperature on the crystallinity of the films were studied. Strongly (110) oriented ZnO films were obtained at a substrate temperature of $350^{\circ}C$. The resistivity was increased to above $3{\times}10^{6}{\Omega}{\cdot}cm$ with copper doping and vapor oxidation.