• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1261-1266
• /
• 2004

Dielectric Barrier Discharge (DBD) in air, which has been established for the production of large quantities of ozone, is more recently being applied to a wider range of aftertreatment processes for HAPs (Hazardous Air Pollutants). Although DBD has high electron density and energy, its potential use as precharging nano and submicron particles are not well known. In this work, we measured I-V characteristics of DBD and estimated collection efficiency of the particles by DBD type 2-stage ESP. To examine the particle collection with various applied voltage waveforms of DBD for nano and submicron sized, bimodal particles were generated by a electrical tube furnace and an atomizer.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.4
• /
• pp.576-581
• /
• 2010

As a super high speed small-sized centrifugal separator which is operated by the center inputting method has solved two difficulty problems, it can be made use of developing the new composition through the making of Nano particle (50~100nm) by high speed revolution and alleviation of unbalanced shapes inside the disk continuously throwing slurry in the central part. Uses the air spindle and the centrifugal machine production will be able to manufacture the Roh class fine particle under boil.

• YAKHAK HOEJI
• /
• v.25 no.4
• /
• pp.193-197
• /
• 1981

Germanium (Ge) content in Zingiberis Rhizoma was determined by flameless atomic absorption spectrometry with a graphite tube atomizer. The Ge content of the cortical layer was 65.mu.g/g, the central cylinder, $98\mu$g/g and the total, $87\mu$g/g. In the effect of the extraction of Ge by various solvents, polar solvent was more effective than the nonpolar one, Especially, water was the most effective solvent. The water extract of Zingiberis Rhizoma, separated by sephadex G-25 gel filtration, was fractionated into 2 peaks at 254nm. Both the peaks showed atomic absorptions of Ge. It may be concluded that the Ge components of Zingiberis Rbizoma exist as the form of an aqueous organic compounds or associated forms with proteins.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1998.04a
• /
• pp.27-27
• /
• 1998

연구소기내에서 원활한 연소를 위하여 액체의 균일하고 완전한 미소분열 문제는 매우 중요한 연구분야라 할 수 있으며, 특히 항공기용 가스터빈 연소기에 사용되는 분사 시스템의 설계시에는 단순한 미소분열 문제뿐 아니라 시동성 향상, 화염의 안정화, 공해물질의 저감 등은 물론 압력 차가 작고 유량범위가 넓으며 공기를 이용한 미립화(Atomization)의 효율이 낮은 영역, 즉, 시동(Start-up) 및 플레임 아웃(Flame-out)근처의 영역에서도 효율적인 미립화가 이루어지도록 고려되어져야 한다.

• Journal of the Korean Ceramic Society
• /
• v.53 no.5
• /
• pp.557-562
• /
• 2016

Pyrophyllite granule powders for thermal spray coating were successfully prepared through spray drying process. To produce a stable slurry, commercial pyrophyllite powder of $45{\mu}m$ in size was ball-milled for reduction of the size to $2{\sim}3{\mu}m$ and a dispersant was added to control the viscosity. Dense and spherical granules (average granule size : $59{\mu}m$) were prepared under conditions of 12,500 rpm for rotation velocity of the atomizer and 100 cps for slurry viscosity. The granules were then heat treated at $1,200^{\circ}C$ for proper handling strength and flow properties. The final granules had an apparent density of $0.725g/cm^3$ and a flow rate of 2.5 g/sec, which represent excellent properties to be used as the granule powder for thermal spray coatings.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.444-445
• /
• 2006

Flying trajectories of fine particles within a size range of $10{\sim}60{\mu}m$ were studied during centrifugal atomizing processes. A FORTRAN program was written by using increment method. Calculation results revealed that the drag force might reach very high value of 522-7800 g for fine powder of $10{\sim}60{\mu}m$. Flying distance in horizontal direction could be shortened if the particles fly obliquely due to the huge drug force. On the other hand, very fine powder could be projected to far distances when the atmosphere flow velocity is much stronger. Fortunately such particles could be contracted within a cylinder closed to the atomizer when the atmosphere flow was weaken or retained in a limited diameter.

• Journal of ILASS-Korea
• /
• v.26 no.1
• /
• pp.33-39
• /
• 2021

Y-jet nozzle has a wide fuel flow rate range and turn-down ratio, thus, it is used in industrial boilers, furnace and agricultural atomizer. However, it has asymmetrical spray characteristics due to the nozzle design factors. Therefore, in this study, asymmetric spraying characteristics of the elliptical Y-jet nozzle was studied by using the lab-scale spray apparatus. As a result, the elliptical Y-jet nozzle had lower gas mass flow rate than circular Y-jet nozzle at same gas pressure, because of bigger shear stress due to the wider inner surface at the elliptical Y-jet nozzle. Larger SMD was measured on the elliptical Y-jet nozzle than the circular Y-jet nozzle. When SMD was measured in the X_Axis direction at the same gas mass flow rate, the elliptical Y-jet nozzle with an aspect ratio of 2:1 showed greater asymmetry than the others.

• Journal of the Korean Magnetics Society
• /
• v.10 no.6
• /
• pp.269-273
• /
• 2000

Fe-l7Cr-2M(M=Si, Nb, Mo) alloy powder was prepared by plasma electrode rotating atomizer and than the alloy powder was formed and sintered. The particle shape of the Fe-l7Cr-2M(M=Si, Nb, Mo) alloy power is spherical. The saturation magnetization of the sintered Fe-17Cr-2Mo and Fe-l7Cr-2Nb alloy are 155 emu/g. The saturation magnetization of the sintered Fe-l7Cr-2Si alloy is less than that of the sintered Fe-l7Cr-2Mo and Fe-l7Cr-2Nb alloy. The amplitude relative permeability of the sintered Fe-l7Cr-2M(M=Si, Nb, Mo) alloy has the maximum value in the range of 3∼5 Oe applied field at forming pressure 12 ton/cm$^2$, sintering temperature 1200$^{\circ}C$, and frequency 1 kHz. Power loss of the sintered Fe-l7Cr-2Nb alloy is 40 mW/cc at applied field, H$\sub$a/=5 Oe, and frequency, f=1 kHz. The power loss of the sintered Fe-l7Cr-2Nb alloy is a half of that of the sintered Fe-l7Cr-2Si and Fe-l7Cr-2Mo alloy.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.6
• /
• pp.567-572
• /
• 2013

In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem, it is difficult to apply to a continuous process such as a R2R(roll to roll) printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, an electrostatic atomizer sprays micro-drops from the solution injected into the capillary with electrostatic force generated by electric potential of about several tens kV. The organic solar cell based on a P3HT/PCBM active layer and a PEDOT:PSS electron blocking layer prepared from ESD method shows solar-to-electrical conversion efficiency of 1.42% at AM 1.5G 1sun light illumination, while 1.86% efficiency is observed when the ESD deposition of P3HT/PCBM is performed on a spin-coated PEDOT:PSS layer.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.24 no.2
• /
• pp.306-315
• /
• 2000

An experimental study was conducted to examine the internal flow patterns inside the mixing chamber of effervescent atomizers. The mixing chamber has the rectangular cross section ($8mm{\times}2mm$) and made of transparent acrylic plate for flow visualization. The parameters tested were the air/liquid ratio (ALR), injection. pressure, and the nozzle orifice diameter. Three different flow regimes were observed; bubbly, annular, and intermittent flows. In the bubbly flow regime, the discharged mixture was disintegrated into drops through the bubble expansion and the ligament breakup. On the other hand, in the annular flow regime, the liquid annulus was disintegrated into small drops by the aerodynamic interaction between the phases due to the high relative velocities between the gas and the liquid. In the intermittent flow regime, the bubble-expansion/ligament-disintegration mode and the annulus-disintegration mode appeared alternatively. The correlations representing the transition criteria between the two-phase flow patterns within the mixing chamber were proposed based on the drift-flux models.