• Korean Journal of Weed Science
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• v.3 no.2
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• pp.190-198
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• 1983

To examine the possibility of enhancing activity of foliar applied herbicides by spray methods and additives, field experiments were conducted to evaluate the effects of surfactant, spray volume, and additions of ammonium sulfate or potassium chloride to glyphosate on toxicity to Digitaria sanguinalis or Artemisia princeps. Glyphosate toxicity increased as spray volume was decreased from 120 1/10a to 40 and 80 1/10a. Additions of surfactant in the spray solution increased toxicity of glyphosate to D. sanguinalis and usually more pronounced effect was obtained at glyphosate 30.5g a.i./10a. Additions of 1 and 5% (w/v) ammonium sulfate to glyphosate increased toxicity to A. princeps at glyphosate 30.5 and 61.5g a.i./10a. 10% ammonium slufate, however, had no effect or were antagonistic. Additions of potassium chloride at 1,2 and 3% (w/v) were also very effective to increase herbicidal activity to A. princeps at glyphosate at 30.5 and 61.0g a.i/10a. These results suggest that the practices for enhancement of herbicidal activity by improvement of spray method and additions of ammonium sulfate or potassium chloride to glyphosate can be employed to use lower herbicide levels while giving the same degree of weed control in orchards and non-crop lands.

• Journal of ILASS-Korea
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• v.17 no.4
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• pp.192-196
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• 2012

This paper reports on breakup characteristics of fuel droplet which includes metal nanoparticles. In order to develop a new injection system for nanoparticle-coated layers overcoming the conventional flame spray system, fundamental experiments were conducted to examine the interaction between a fuel droplet with nanoparticles and the external energy induced by the laser. In the experiments, this study used nickel nanoparticles whose size was under 100 nm to mix with kerosene as the fuel, and utilized a syringe pump and a metal needle to inject a fuel droplet. In particular, the Nd-YAG laser was adopted to give additional energy to the nanoparticles for evaporation of a fuel droplet containing nanoparticles. When the laser energy as 96 mJ was irradiated during the injection, it was observed that such an explosive evaporation occurred to break up a fuel droplet including nanoparticles, making the rapid increase in the ratio surface area to liquid volume. From this work, we suggest the possibility that the laser energy can be used for rapid evaporation of a fuel droplet.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.5
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• pp.96-104
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• 2001

The present study experimentally investigates the concentration distribution of liquid and vapor phase with different injection timings in the in-cylinder flow field of a optically accessible engine. The conventional MPI, DOHC engine was modified into DI gasoline engine. The images of liquid and vapor phases in the motoring engine were captured by using exciplex fluorescence method. Dopants used in this study were 2% fluorobenzene and 9% DEMA(diethyl-methyl-amino) in 89% solution of hexane by volume respectively. Two dimensional spray fluorescence images of liquid and vapor phases were acquired to analyze spray behaviors and fuel distribution in the in-cylinder flow field. Measurements were carried out fur four different injection timings, namely BTDC 270$^{\circ}$, 180$^{\circ}$, 90$^{\circ}$, and 50$^{\circ}$. Experimental results indicate that behaviors and distribution of vapor phase were largely affected by in-cylinder tumble flow, and mixture formation process was also greatly affected by in-cylinder flow at early injection mode and by ambient pressure at late injection mode.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.566-574
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• 1988

A study is described for obtaining real time in situ size and velocity measurements of the spray-droplet using crossed-beam interferometry. The optical arrangement is similar to dual-beam laser Doppler velocimetry(LDV). Droplets passing trough the probe volume scatter light to the collecting lens placed at 90.deg. off-axis angle. The dual-beam light scatter is analyzed by the geometric optics theory to relate the scattered fringe pattern to droplet diameter. The droplet size measurement is based upon the signal visibility. As the system is based on the Doppler effect, a single component of velocity is velocity is extracted concurrent with the size information. The validity of the method is evaluated by comparing its performance to widely accepted but limited technique, the collection method. By using 90.deg. off-axis scatter detection angle, the measurement of the droplet size and velocity distributions, and the local correlations between droplet sizes and velocities in relatively dense spray environments are made possible.

• Journal of Mechanical Science and Technology
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• v.14 no.10
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• pp.1143-1150
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• 2000

The effects of ambient conditions on vaporizing sprays from a high-pressure swirl injector were investigated by an exciplex fluorescence method. Dopants used were 2% fluorobenzene and 9% DEMA (diethyl-methyl-amine) in 89% solution of hexane by volume. In order to examine the behavior of liquid and vapor phases inside of vaporizing sprays, ambient temperatures and pressures similar to engine atmospheres were set. It was found that the ambient pressure had a significant effect on the axial growth of spray, while ambient temperature had a great influence on the radial growth. The spatial distribution of vapor phase at temperatures above 473K became wider than that of liquid phase after half of injection duration. From the analysis of the area ratio for each phase, the middle part (region II) in the divided region was the region which liquid and vapor phases intersect. For liquid phase, fluorescence-intensity ratio was greatly changed at lms after the start of injection. However, the ratio of vapor phase was nearly uniform in each divided region throughout the injection.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.5
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• pp.433-439
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• 2012

Anticorrosive paint is the most widely used in shipbuilding and the dry film thickness is very important in terms of productivity and assurance of anticorrosive performance. However, it is difficult to achieve the recommended target film thickness because the dry film thickness depends on labor's skill in practice and is affected by a number of parameters, such as spray pressure, paint flow rate, tip size, spray distance, SVR(Solid Volume Ratio), etc. Present paper derives an empirical equation through the correlation analysis of parameters selected by spray experiments of anti corrosive painting in order to predict the coated status. Comparing the calculated results with practical data, we show that the empirical equation can successfully expect DFT(Dry Film Thickness).

• Journal of Powder Materials
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• v.17 no.3
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• pp.209-215
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• 2010

Mesoporous alumina particles were prepared by spray pyrolysis using cetyltrimethyl-ammonium bromide (CTAB) as a structure directing agent and the effect of Al precursor types on the texture properties was studied using $N_2$ adsorption isotherms, small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The surface area and the microstructure of alumina particles were significantly influenced by the Al precursor type. The largest BET surface area was obtained when Al chloride was used, whereas alumina particles prepared from Al acetate had the largest pore volume. According to small-angle X-ray scattering (SAXS) analysis, the alumina powders prepared using nitrate and acetate precursors had a clear single SAXS peak around $2{\theta}=1.0{\sim}1.5^{\circ}$, indicating that regular mesopores with sponge-like structure were produced. On the basis of TEM, SAXS, and $N_2$ isotherm results, the chloride precursor was most profitable to obtain the largest surface area ($265\;m^2/g$), whereas, the nitrate precursor is useful for the preparation of non-hollow mesoporous alumina with regular pore size, maintaining high surface area (${\sim}233\;m^2/g$).

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.172-180
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• 2006

This study was to analyze the effect of mixed fuel composition and mass fraction on the characteristics of evaporating diesel spray and combustion under the various ambient conditions. The characteristics of vaporization distribution and combustion were visualized by laser induced fluorescent method and direct photography. The experiments were conducted in the constant volume vessel and rapid compression expansion machine with optical access. Multi-component fuels mixed i-octane, n-dodecane and n-hexadecane were injected the vessel and rapid compression expansion machine with electronically controlled common rail injector. Experimental results show that fuel vapor formed stratified distribution. And vaporization and diffusion are become actively increasing in mass fraction of low boiling point component. Consequently multi-component fuels were expected to control the evaporating behavior according to their suitable mass fraction.

• Journal of Power System Engineering
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• v.21 no.4
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• pp.34-41
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• 2017

Diesel engines with compression-ignition type have superior thermal efficiency, durability and reliability compared to gasoline engine. To control emitted gas from the engines, it can be applied to alternative fuel without any modification to the engine. Therefore, in this study, as a basic study for applying emulsified fuel to the actual diesel engine, analysis of spray behavior characteristics of emulsified fuel was carried out simultaneously by experimental and numerical method. The emulsified fuel consist of diesel, hydrogen peroxide, and surfactant. The surfactant for manufacturing emulsified fuel is comprised of span 80 and tween 80 mixed as 9:1 and fixed with 3% of the total volume of the emulsified fuel. In addition, six kinds of emulsified fuel(EF0, EF2, EF12, EF22, EF32, and EF42) were manufactured according to the mixing ratio of hydrogen peroxide. The droplet and spray experiments were performed to observe the behavior characteristics of the emulsified fuel. The numerical analysis was carried out using ANSYS CFX to confirm the microscopic behavior characteristics. Consequently, rapid mixture formation can be expected due to evaporation of hydrogen peroxide in emulsified fuel, and it is confirmed that Reitz&Diwakar breakup model is most suitable as breakup model to be applied to the numerical analysis.

• Journal of the Korean Ceramic Society
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• v.56 no.1
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• pp.65-70
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• 2019

Simple fabrication of a powdered Ge-reduced graphene oxide (Ge-rGO) composite via spray pyrolysis and reduction is introduced herein. Successful incorporation of the rGO nanosheets with Ge hindered the aggregation of Ge and conferred enhanced structural stability to the composite by alleviating the mechanical stress associated with drastic volume changes during repeated cycling. The Li-ion storage performance of Ge-rGO was compared with that of powdered Ge metal. The reversible discharge capacity of Ge-rGO at the $200^{th}$ cycle was $748mA\;h\;g^{-1}$ at a current density of $1.0A\;g^{-1}$ and Ge-rGO showed a capacity of $375mA\;h\;g^{-1}$ even at a high current density of $5.0A\;g^{-1}$. The excellent performance of Ge-rGO is attributed to the structural robustness, enhanced electrical conductivity, and formation of open channels between the rGO nanosheets, which facilitated electrolyte penetration for improved Li-ion diffusion.