• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.164-170
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• 1996

Among after treatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects on factors of oxidaton characteristics and conversion efficiency of DOC. We tested to estimate change of engine performance whether a 11,000cc diesel engine equipps with DOC or not. We conducted test to estimate the reduction efficiency of exhaust gas in P-5 mode, in D-13 mode of heavy duty diesel regulation mode and in somoke opacity mode for two samples and also we conducted test to analyze the effects about both exhaust gas velocities 1,100rpm and 2,200rpm

• Korean journal of applied entomology
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• v.51 no.1
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• pp.67-72
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• 2012

This study was conducted to evaluate the scouting methods for larva and adults of the alfalfa weevil, $Hypera$ $postica$ Gyllenhal on Chinese milkvetch, $Astragalus$ $sinicus$ L. in the field. Three sampling methods, shake-bucket, shake-picking, and a sweeping net were evaluated for collecting alfalfa weevil larvae. We found significant differences among scouting methods and date in all survey fields. Sweep-net sampling was less able to detect small larvae than large larvae, which were not detected until early April whereas the shake-bucket, and shake-picking methods efficiently collected larvae from middle March. A Pitfall trap with three different baits - no bait, kidney bean seeds and sprouting kidney beans were compared for collection efficiency of alfalfa weevil adults. Collection efficiencies were significantly different by bait(p<0.018). Traps baited with sprouting kidney beans were the most efficient for collecting the alfalfa weevil. The number of alfalfa weevil caught was not significantly different between kidney bean seed and no bait in the pitfall trap. Therefore, the shake-bucket method for larvae and a pitfall trap baited with sprouting kidney beans for adults are recommended for scouting of the alfalfa weevil in a Chinese milkvetch field.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.443-448
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• 2015

The attractant effect to Platypus koryoensis (Murayama), an insect vector of Korean oak wilt disease, was determined using a multi-funnel trap and trap logs treated with ethanol and ethanol extract of the bark of the Mongolian oak Quercus mongolica (Fisher). The number of entrance holes in ethanol and bark ethanol extract treatments was higher than that in the control (blank bottle). However, the number of entrance holes in ethanol and bark ethanol extract treatments was not significantly different. The number of entrance holes in the logs increased with increase in diameter of the logs. The lower part of the trap logs had significantly more number of entrance holes than that in the upper part (p < 0.05). The lower part of trap logs tends to be rarely exposed to direct sunlight resulting in desiccation of the logs, which in turn provides good conditions for microbial growth, a food source for P. koryoensis. The results show, that ethanol could be used effectively in the monitoring and maintenance of P. koryoensis because of the cheaper cost of ethanol than bark ethanol extracts, and thus, having a higher economical advantage. Further research of oak bark ethanol extracts is necessary to improve its efficiency.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.8
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• pp.789-798
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• 2011

We carry out an experimental investigation to analyze the basic performance of NO(nitric oxide) storage in a lean phase and also analyze the NO reduction achieved by the spraying of reducing agents in the rich phase of the exhaust gas in an LNT(Lean NOx Trap). This is an after-treatment system used to reduce the NOx emissions from a diesel engine. If the stored NO is reduced, we measure the outlet concentration downstream of the LNT. The test LNT material used in the experiments is commercial LNT. After being canned into stainless-steel(SUS304), it was built in a micro bench-flow reactor. Compositions of feed gases, three heated and three no heated gases were sprayed upstream of the LNT to analyze the characteristics. We use various temperatures and space velocities as response variables.

• Journal of Biomedical Engineering Research
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• v.34 no.4
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• pp.189-196
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• 2013

Dielectrophoresis(DEP) is useful in manipulation and separation of micro-sized particles including biological samples such as bacteria, blood cells, and cancer cells in a micro-fluidic device. Especially, those separation and manipulation techniques using DEP in combination of micro fabrication technique have been researched more and more. Recently, it is revealed that a window structure of insulating layer in microfluidic DEP chip is key role in trap of micro-particles around the window structure. However, the trap phenomenon-driven by DEP force gradient did not fully understand and is still illusive. In this study, we characterize the trap mechanism and efficiency with different shapes of window in a microfluidic DEP chip. To do this characterization, we fabricated 4 different windows shapes such as rhombus, circle, squares, and hexagon inside a micro-fluidic chip, and performed micro-sized particles manipulation experiments as varying the frequency and voltage of AC signal. Moreover, the numerical simulation with the same parameters that were used in the experiment was also performed in order to compare the simulation results and the experimental results. Those comparison shows that both results are closely matched. This study may be helpful in design and development of microfluidic DEP chip for trapping micro-scaled biological particle.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.124-129
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• 2010

The direct injection (DI) diesel engine has become a prime candidate for future transportation needs because of its high thermal efficiency. However, nitrogen oxides (NOx) increase in the local high temperature regions and particulate matter (PM) increases in the diffusion flame region within diesel combustion. Therefore, the demand for developing hybrid system consist of exhaust gas recirculation (EGR) and aftertreatment system as well as diesel particulate filter (DPF) or lean NOx trap (LNT) should be applied. The variation of EGR rate due to the malfunction of EGR valve can affect not only the combustion stability of engine but also the performance of aftertreatment system. In this research, 2.0 liter 4-cylinder turbocharged diesel engine was used to investigate the combustion and emission characteristics for various operating conditions with EGR. While the fuel consumption was increased with increase of EGR rate, NOx emission was improved by maximum 90% at low speed, low load operating condition. To achieve combustion stability and reliability of aftertrearment system with minimum penalty in fuel consumption and emissions, the fault diagnosis of EGR malfunction must be employed.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.468-471
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• 2009

This study was conducted to determine the phototactic response of Paratlanticus ussuriensis to different wavelength of light by the use of LEDs and to provide a basic information for developing an improved trap with the longer trapping efficiency to control environment-friendly this katydid. P. ussuriensis were attracted to the single LED light source, especially, blue and white. For the multiple LED light sources, the movement of P. ussuriensis was not significantly different among LED-light bands. Overall, P. ussuriensis had a tendency to move to light source although they were not attracted to a specific wavelength of light. These methods may be used as information for conducting a phototactic response of other insects.

• Journal of Photoscience
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• v.3 no.2
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• pp.77-83
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• 1996

Photosensitization via the singlet oxygen ($^1O_2$) mechanism by the binuclear iron-sulfur center, denoted as [2Fe-2S], was investigated, using a highly purified ferredoxin (Fd) preparation from spinach leaves. Since the apoprotein of Fd contains a good number of amino acid residues that are readily reactive with $^1O_2$ and thus interfere with the detection of $^1O_2$ generated from [2Fe-2S], we attempted to deprive the $^1O_2$-sensitive residues of their $^1O_2$-scavenging capacity as much as possible by treating Fd with rose bengal plus 550 nm monochromatic light and thereby photooxidatively degrading these residues. The photochemically modified Fd was found to keep the structural integrity of its Fe-S group virtually unaffected by the treatment. By employing chemical trap method for measurement and examining the kinetic effects of azide and deuterium oxide on the reactions of $^1O_2$ with various trap compounds, we were able to demonstrate that [2Fe-2S] indeed acts as a photosensitizer via $^1O_2$. Further, the minimum quantum yield of $^1O_2$ production by [2Fe-2S] was estimated to be 0.0047.

• Proceedings of the Botanical Society of Korea Conference
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• 1985.08b
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• pp.59-71
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• 1985

In rice, limited efforts have been made to identify genes by the use of insertional mutagens, especially heterologous transposons such as the maize Ac/Ds. We constructed Ac and gene trap Ds vectors and introduced them into the rice genome by Agrobacterium-mediated transformation. In this report, rice plants that contained single and simple insertions of T-DNA were analyzed in order to evaluate the gene-tagging efficiency. The 3'end of Ds was examined for putative splicing donor sites. As observed in maize, three splice donor sites were identified at the 3'end of the Ds in rice. Nearly 80% of Ds elements wered excised from the original T-DNA sites, when Ac cDNA was expressed under a CaMV 35S promoter. Repetitive ratoon culturing was performed to induce new transpositions of Ds in new plants derived from cuttings. About 30% of the plants carried at least one Ds that underwent secondary transposition in the later cultures. 8% of transposed Ds elements expressed GUS in various tissues of rice panicles. With cloned DNA adjacent to Ds, the genomic complexities of the insertion sites were examined by Southern hybridization. Half of the Ds insertion sites showed simple hybriodization patterns which could be easily utilized to locate the Ds. Our data demonstrate that the Ac/Ds mediated gene trap system could prove an excellent tool for the analysis of functions of genes in rice. We discuss genetic strategies that could be employed in a largee scale mutagenesis using a heterologous Ac/Ds family in rice.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.3
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• pp.75-80
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• 2006

Since air pollution has become a globally critical issue and exhaust emissions from automobiles cause a major source of air pollution, many countries including advanced countries have stipulated stringent emission regulations. Particularly in diesel vehicles, NOx and particulate matters exhaust in significant amounts even though diesel vehicles provide merits in aspects of higher thermal efficiency and lower $CO_2$. To reduce Particulate matters and NOx, after-treatment technology such as filter trap, oxidation catalysts and EGR has been applied. This test was conducted on the effect of continuous regeneration diesel particulate filter and cooled-EGR, and 15ppm low sulfur diesel was used as a test fuel. Exhaust emissions, PM, NOx, CO, HC and Soots were measured and compared under D-13 and D-3 modes.