• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3019-3025
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• 2008

An experimental study was performed to assess the effect of diesel and JP-8 aviation fuel on the spray characteristics, performance and emissions in a single cylinder optical diesel engine. Both fuels were injected via an 8-hole solenoid-driven injector in a common-rail injection system. For better understanding of spray development, the macroscopic images were captured with high speed camera, offered evidences for the results of performance and emissions. From macroscopic spray images, the spray tip penetration of JP-8 shorter than that of diesel while spray angle of JP-8 was wider than that of diesel. It indicates that the vaporization of JP-8 is superior to that of diesel. The lower cetane number of JP-8 resulted in increased portion of premixed combustion. The IMEP with JP-8 is lower than that of diesel-fueled engine. Especially, using JP-8 has a potential for reducing soot.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.74-82
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• 2004

Planar laser-induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Acetone PLIF is chosen because fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone PLIF is applied to measure quantitative air excess ratio distribution in an engine fueled with LPG. Acetone is excited by KrF excimer laser (248nm) and its fluorescence image is acquired by ICCD camera with a cut-off filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF signal, an image processing method including the correction of laser sheet beam profile is suggested. Raw images are divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which is taken by a calibration process, are converted to air excess ratio distribution. This investigation shows instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.

• Journal of Environmental Science International
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• v.28 no.7
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• pp.607-615
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• 2019

The purpose of this study is to biological treatment of high salinity wastewater using Aerobic Granular Sludge (AGS). In laboratory scale's experiments research was performed using a sequencing batch reactor, and evaluation of the denitrification reaction in accordance with the injection condition of salinity concentration, surface properties of microorganisms, and sludge precipitability was performed. The results showed that the salinity concentration increased up to 1.5%, and there was no significant difference in the nitrogen removal efficiency; however, it showed a tendency to decrease gradually from 2.0% onward. The specific denitrification rate (SDNR) was 0.052 - 0.134 mg $NO_3{^-}-N/mg$ MLVSS (mixed liquor volatile suspended solid)${\cdot}day$. The MLVSS/MLSS (mixed liquor suspended solid) ratio decreased to 76.2%, and sludge volume index ($SVI_{30}$) was finally lowered to 57 mL/g. Using an optical microscope, it was also observed that the initial size of the sludge was 0.2 mm, and finally it was formed to 0.8-1.0 mm. Therefore, salinity injection provides favorable conditions for the formation of an AGS, and it was possible to maintain stable granular sludge during long-term operation of the biological treatment system.

• Journal of Korean Medicine Rehabilitation
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• v.20 no.1
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• pp.27-36
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• 2010

Objectives : We investigated the role of intracellular calcium chelator, bis-(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid(BAPTA), on the modulation of phosphorylation of the spinal N-methyl-D-aspartate receptor(NMDAR) NR1 and NR2B subunits following electroacupuncture(EA). Methods : Bilateral 2 Hz EA stimulation with 1.0 mA was delivered at those acupoints corresponding to Zusanli(ST36) and Sanyinjiao(SP6) in man via needles for 30min. Results : EA analgesia was reduced by intra-peritoneal injection at a higher dose of BAPTA from termination of EA stimulation. At 60 min after EA treatment, the total number of c-fos-immunostained neurons in each regions of the dorsal horn in the $L_{4-5}$ segments was decreased by BAPTA injection, especially in nucleus proprius. The mean integrated optical density (IOD) of NR1 and NR2B subunits were increased only in superficial laminae of EA-treated rats when compared with normal rats. However, the mean IOD of pNR1 was significantly decreased by BAPTA injection in both the superficial laminae and neck region and pNR2B in the superficial laminae. Western blot analyses confirmed the decreased expression of pNR1 and pNR2B. Conclusions : We concluded that intracellular calcium may well play an important role in EA analgesia by modulating the phosphorylation state of spinal NMDAR subunits.

• Clean Technology
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• v.29 no.4
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• pp.244-248
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• 2023

Recently, displays play an important role in quickly delivering a lot of information. Research is underway to reproduce various colors close to natural colors. In particular, research is being conducted on the light emitting structure of displays as a method of expressing accurate and rich colors. Due to the advancement of technology and the miniaturization of devices, the need for small but high visibility displays with high efficiency in energy consumption continues to increase. Efforts are being made in various ways to improve OLED efficiency, such as improving carrier injection, structuring devices that can efficiently recombine electrons and holes in a numerical balance, and developing materials with high luminous efficiency. In this study, the electrical and optical properties of the seven-layer stacked structure rear-light emitting blue OLED device were analyzed. 4,4'-Bis(carazol-9-yl)biphenyl:Ir(difppy)2(pic), a blue light emitting material that is easy to manufacture and can be highly efficient and brightened, was used. OLED device manufacturing was performed via the in-situ method in a high vacuum state of 5×10-8 Torr or less using a Sunicel Plus 200 system. The experiment was conducted with a seven-layer structure in which an electron or hole blocking layer (EBL or HBL) was added to a five-layer structure in which an electron or hole injection layer (EIL or HIL) or an electron or hole transport layer (ETL or HTL) was added. Analysis of the electrical and optical properties showed that the device that prevented color diffusion by inserting an EBL layer and a HBL layer showed excellent color purity. The results of this study are expected to greatly contribute to the R&D foundation and practical use of blue OLED display devices.

• Journal of the Korea Convergence Society
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• v.6 no.1
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• pp.43-48
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• 2015

We studied on the injection molding conditions of defect-free PMMA lens for surgical light. When the heat temperature of mold is low, more imperfect molding or weldlines and flow marks have showed. A defective lens depends on low fluidity of the PMMA resin and its temperature is high, a flexural strain has occurred. The longer cooling time of specimens, the more cracks have occurred due to resin crystallization. In this study, optimal molding conditions for defect-free PMMA lens is as follows. The heat temperature of core mold was 110 [$^{\circ}C$] and also the cooling time was 25 [sec]. PMMA materials can realized low expense to produce plastic optical lens and applications.

• The korean journal of orthodontics
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• v.50 no.6
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• pp.401-406
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• 2020

Objective: To investigate and compare the slot sizes and parallelism of metal injection molding (MIM) and computerized numerical control (CNC) brackets. Methods: The following four MIM bracket series with 0.022-inch (in) slots were selected for investigation: Di MIM mini Twin (Ortho Organizers), Mini Diamond Roth (Ormco), Gemini MBT (3M Unitek), and Formula R Roth (Tomy). The following four CNC bracket series with 0.022-in slots were selected for investigation: Econoline MBT (Adenta), Legend mini MBT (GC Orthodontics), Crown mini MBT (Adenta), and Evolve MBT (DB Orthodontics). The slot dimensions were measured using an optical microscope (XTCam-D310M; Mitutoyo) with a resolution of 1 ㎛. The results were statistically analyzed using one-way analysis of variance and the Tukey post-hoc test with a significance level of 0.05. Results: The results indicated that all the investigated slot sizes were oversized with respect to the manufacturers' specifications (0.022 in). Among the eight bracket series, the Di MIM bracket (MIM) was the most oversized by 10.4%, whereas the Evolve bracket (CNC) was the least oversized by 2.6%. The slots in seven of the bracket series had divergent walls instead of parallel ones. The Evolve bracket alone had parallel slot walls. Conclusions: Regardless of the manufacturing method, all the slot sizes of the brackets investigated in this study were significantly oversized; most of the slot walls were nonparallel, except for those of the Evolve bracket. This study could not establish that the CNC method was more accurate than the MIM method in manufacturing bracket slots.

• Composites Research
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• v.27 no.2
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• pp.52-58
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• 2014

Short fiber reinforced composites manufactured by injection molding have diverse fiber orientations variable with measuring positions even in the same specimen, which is caused by the flow induced fiber orientation. Fiber orientations considerably affect the mechanical and thermal properties of final composite products. In this study, fiber orientation of injection molded carbon fiber reinforced PA6/PPO composite was measured at several points of the specimen by optical microscopy analysis and the corresponding izod impact strength, coefficients of thermal expansion (CTE) were also measured to investigate the influence of local fiber orientation on the mechanical and thermal properties. Izod impact strength where fiber was perpendicular to the direction of crack propagation was higher than where fiber was parallel to the direction, which could be explained be the impact resistance reinforcing mechanism by fiber orientation. CTE was also lower where fiber was parallel to the measurement direction of CTE than where fiber was perpendicular to the direction, which could be also explained by the dimensional stability mechanism by fiber orientation.

• Korean Journal of Optics and Photonics
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• v.20 no.3
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• pp.182-188
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• 2009

The surface plasmon resonance ellipsometer (SPRE), using a multiple air injection system with an extraction of air system, has been proposed and developed to minimize measurement error of signals due to diffusion of reagent into running buffer. Since the diffusion of reagent into running buffer affects the refractive index of the running buffer by changing the concentration, characteristics of binding between various bio-molecules don't appear clearly in measurement results. The diffusion between running buffer and reagent can be blocked by using an air bubble injection system. An extraction of air system is used to remove the noise signal due to unnecessary air bubbles flowing in a channel. Reliability of measurement results has been improved by using the valve system.

• Tuberculosis and Respiratory Diseases
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• v.77 no.3
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• pp.116-123
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• 2014

Background: Mesenchymal stem cells (MSCs) obtained from bone marrow or adipose tissue can successfully repair emphysematous animal lungs, which is a characteristic of chronic obstructive pulmonary disease. Here, we describe the cellular distribution of MSCs that were intravenously injected into mice with elastase-induced emphysema. The distributions were also compared to the distributions in control mice without emphysema. Methods: We used fluorescence optical imaging with quantum dots (QDs) to track intravenously injected MSCs. In addition, we used a human Alu sequence-based real-time polymerase chain reaction method to assess the lungs, liver, kidney, and spleen in mice with elastase-induced emphysema and control mice at 1, 4, 24, 72, and 168 hours after MSCs injection. Results: The injected MSCs were detected with QD fluorescence at 1- and 4-hour postinjection, and the human Alu sequence was detected at 1-, 4- and 24-hour postinjection in control mice (lungs only). Injected MSCs remained more in mice with elastase-induced emphysema at 1, 4, and 24 hours after MSCs injection than the control lungs without emphysema. Conclusion: In conclusion, our results show that injected MSCs were observed at 1 and 4 hours post injection and more MSCs remain in lungs with emphysema.