• Asian-Australasian Journal of Animal Sciences
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• 제30권6호
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• pp.781-787
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• 2017

Objective: The early growth response (Egr) family consists of four members (Egr1, Egr2, Egr3, and Egr4) that are zinc finger transcription factors. Among them, Egr3 is involved in transcriptional regulation of target genes during muscle spindle formation and neurite outgrowth. We previously showed that the immunoreactive Egr3 is localized on oocyte spindle and accumulate near the microtubule organizing center during meiosis I in mice. Egr3 was also shown to be localized on spermatocytes. We herein investigated if Egr3 is expressed in mouse gonads and if Egr3 blockade results in any defect in oocyte maturation. Methods: Expression of Egr3 in mouse gonads was examined by reverse transcription-polymerase chain reaction. Full-length Egr3 and truncated Egr3 (${\Delta}Egr3$) complementary RNAs (cRNAs) with Xpress tag at N-terminus and DsRed2 at C-terminus, and small interfering RNA (siRNA) targeting Egr3 were microinjected into mouse oocytes at germinal vesicle stage. Localization of microinjected Egr3 was examined by confocal live imaging and immunofluorescence staining. Results: Egr3 mRNA was detected in mouse ovaries and testes from 1 to 4 week-old mice. An uncharacterized longer transcript containing 5'untranslated region was also detected in 3 and 4 week-old gonads. Microinjected Xpress-Egr3-DsRed2 or Xpress-${\Delta}Egr3$-DsRed2 localized to nuclei and chromosomes during meiotic progression. Microinjection of these cRNAs or Egr3 siRNA in oocytes did not affect meiotic maturation. Immunofluorescence staining of Egr3 in Xpress-${\Delta}Egr3$-DsRed2-injected oocytes showed a positive signal only on meiotic spindle, suggesting that this antibody does not detect endogenous or exogenous Egr3 in mouse oocytes. Conclusion: The results show that Egr3 localizes to chromosomes during meiotic progression and that certain antibodies may not faithfully represent localization of target proteins in oocytes. Egr3 seems to be dispensable during oocyte maturation in mice.

• 에너지공학
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• 제11권3호
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• pp.203-209
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• 2002

본 연구에서는 유니크에서 개발된 E-EGR 밸브의 특성을 분석하였으며, 차량적용의 가능성을 평가하였다. 메르세데스 벤츠에서 개발된 배기량 0.8리터급 소형디젤 승용차인 Smart cat가 본 실험에 사용되어졌다. 실험용 차량은 전자식 EGR 밸브가 장착된 3기통의 터보 과급식 차량이다. 테스트벤치에서 EGR 밸브의 성능을 비교 및 분석한 후 차대동력계상에서 EGR map과 CVS-75 시험결과를 통하여 전자식 EGR 밸브의 차량적용 가능성을 여부를 수행하였다.

• 한국연소학회지
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• 제19권3호
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• pp.26-33
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• 2014

We examined the characteristics of $NO_x$ emission for CH4/air non-premixed flames using the exhaust gas recirculation(EGR) methods, which are the air-induced EGR(AI-EGR) and fuel-induced EGR(FI-EGR) methods. Our experimental results show that the $NO_x$ emission index($EI_{NOx}$) decreased with increasing EGR ratio. In the range needed to form a stable flame, the reduction rate of $EI_{NOx}$ for the FI-EGR method was approximately 29% when the EGR ratio was 20%, and the reduction rate for the AI-EGR method was approximately 28% with 25% of the EGR ratio. According to the flame structure based on numerical results, high temperature regions for the FI-EGR method were narrower and lower than those for the AI-EGR method at the same EGR ratio. Furthermore, based on the experimental results for swirl flames, the reduction rate of $EI_{NOx}$ for the FI-EGR method was approximately 49% with 15% of the EGR ratio, while the maximum reduction rate for AI-EGR method was approximately 45% with 25% of the EGR ratio. Consequently, we verified that the FI-EGR method was more effective than the AI-EGR method in reducing $NO_x$ emission for non-premixed flames with EGR. We expect that the results of this study will provide fundamental information relating to hybrid combustion systems, which can be used in the design of combustion systems in the future.

• Journal of Advanced Marine Engineering and Technology
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• 제35권4호
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• pp.379-387
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• 2011

최근 디젤엔진에서 엔진성능향상 및 배출가스저감을 위해 저압 EGR시스템에 대하여 연구개발이 활발히 진행되고 있다. 저압 EGR시스템은 EGR율에 따라 과급압력이 영향을 받지 않기 때문에 PM을 최소 화하면서 $NO_x$를 저감할 수 있는 장점을 갖고 있다. 본 연구에서는 2.0L급 고속직분사방식의 엔진에서 출력 및 연비저하로 EGR적용이 어려운 엔진회전수 2000 rpm, BMEP 1.0 MPa, 과급압력 181.3 kPa인 중부하 운전영역에서 서로 다른 EGR시스템에 따른 엔진성능 및 배출가스 특성을 실험적으로 연구하였다. 그 결과로서 기존의 고압 EGR시스템 또는 배압조절밸브를 사용하는 저압 EGR시스템에 비하여 ETC를 적용한 저압 EGR시스템이 $NO_x$ 배출특성은 큰 차이가 없는 반면에, 연비 및 열효율이 향상되고 PM 저감에 연소효과를 나타내고 있음을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.928-933
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• 2001

EGR(Exhaust Gas Recirculation) is an effective strategy to control nitrogen oxides emissions from diesel engine. The EGR reduces $NO_x$ through lowering the oxygen concentration in the combustion chamber as well as through heat absorption. However, application of EGR system is difficult because of the penalty in fuel consumption and the increase in particulate matter. The engine used for the experimental was a 3-cylinder 0.8-liter turbo-charged light duty diesel engine with an electronic EGR valve. In this study, experiments were performed at variable vehicle speeds and loads on the chassis dynamometer. To evaluate the exhaust emissions with the EGR system testing was performed using cvs-75 mode test procedure. Results of the cvs-75 mode test achieve sufficiently to meet EURO3 standards.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.65-73
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• 2007

The use of an Exhaust Gas Recirculation(EGR) for a diesel engine with variable geometry turbocharger(VGT) has confronted how to obtain the amount of EGR for NOx reduction requirement at wide operating range and less side effect. Through a combined effort of modeling(wave action simulation) and experiment, an investigation into the effect of EGR area ratio and pipe length on EGR characteristics of common rail diesel engine with VGT has been performed. For accurate computation, calibration of constants involved in empirical and semi-empirical correlations has been performed at a specific operating point, before of its use for engine simulation. From the results of this study, it was found that EGR rate is sharply increased with increasing EGR area ratio until area ratio of 0.3. However, the effect of EGR area ratio on EGR rate is negligible beyond this criteria. This study also investigates the effect of EGR pipe length on a EGR amount and pulsating flow characteristics at EGR junction. The results showed that the longer EGR pipe length, the lower EGR amount was achieved due to the flow loss resulting in lower amplitude of pressure wave.

• 생물정신의학
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• 제29권2호
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• pp.33-39
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• 2022

Objectives The early growth response 3 (EGR3) gene located in chromosome 8p21.3 is one of the susceptibility loci in many psychiatric disorders. EGR3 gene plays critical roles in signal transduction in the brain, which is involved in neuronal plasticity, neuronal development, learning, memory, and circadian rhythms. Recent studies have suggested EGR3 as a potential susceptibility gene for bipolar disorder (BPD). However, this requires further replication with an independent sample set. Methods To investigate the genetic role of EGR3 in Korean patients, we genotyped six single-nucleotide polymorphisms (SNPs) in the chromosome region of EGR3 in 1076 Korean BPD patients and 773 healthy control subjects. Results Among the six examined SNPs of EGR3 (rs17088531, rs1996147, rs3750192, rs35201266, rs7009708, rs1008949), SNP rs35201266, rs7009708, rs1008949 showed a significant association with BPD (p = 0.0041 for rs35201266 and BPD2, p = 0.0074 for rs1008949 and BPD, p = 0.0052 for rs1008949 and BPD1), which withstand multiple testing correction. In addition, the 'G-C-C-C' and 'G-C-G-C' haplotypes of EGR3 were overrepresented in the patients with BPD (p = 0.0055, < 0.0001, respectively) and the 'G-T-G-C' haplotype of EGR3 was underrepresented in patients with BPD (p = 0.0040). Conclusions In summary, our study supports the association of EGR3 with BPD in Korean population sample, and EGR3 could be suggested as a compelling susceptibility gene in BPD.

• 대한기계학회논문집B
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• 제37권10호
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• pp.879-886
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• 2013

본 연구에서는 고농도 EGR을 사용하는 DME 예혼합압축자기착화 연소의 근본적인 연소메커니즘을 이해하기 위해 수치해석 시뮬레이션을 수행하였다. EGR과 과급의 영향을 조사하면서 동시에 산소 분압과 산소 농도중 어느 것이 LTR 발열비율을 결정하는 핵심요소인지 확인하였다. EGR 비율과 과급압력을 매개변수 정하기 위해서 1) EGR 비율변화에 따라 산소농도, 산소함유량을 변화시키는 조건 2) 산소농도를 거의 일정하게 유지하면서 과급을 하여 산소 분압을 변화시키는 조건, 3) EGR과 과급을 조합하면서 산소 분압을 일정하게 유지 하기 위해 산소농도를 변화시키는 조건 세가지 조건에서 화학반응수치계산을 수행하여 검증했다. 연구결과 EGR율이 증가하면 연소의 시작, 종료시기가 지연되고, 과급을 하게 되면 연소의 시작, 종료시기가 앞당겨지는 것을 확인했다. EGR과 과급이 LTHR 발열비율 증가에 영향을 미치는 것도 확인하였다.

• 대한기계학회논문집A
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• 제34권3호
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• pp.291-298
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• 2010

본 논문은 자동차 디젤엔진의 EGR 시스템에 사용되는 EGR 냉각기의 열교환 효율에 관한 것으로 배기가스의 냉각수 사이의 열교환을 촉진시키기 위한 방법으로 딤플형 EGR 냉각기를 설계 및 그 성능을 평가하였다. 개발초기 단계에서 딤플형 EGR 냉각기의 성능을 평가하기 위하여 기존 스파이럴 타입의 EGR 냉각기와 딤플형 EGR 냉각기의 전열면적을 비교하였으며, 균질화 기법을 이용한 유한요소해석을 통하여 딤플형 EGR 냉각기의 구조 건전성을 평가하였다. 또한, 딤플형 열교환 튜브의 생산공정-딤플성형, edge bending, center v-notch bending, 압착, 플라즈마 용접-을 체계화하였다. 최종적으로 본 연구를 통하여 딤플형 EGR 냉각기를 개발하였으며, 그 성능을 검증하였다.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4137-4144
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• 2010

본 논문에서는 승용디젤엔진에서 유해배출물을 저감시키는 동시에 고연비를 달성하기 위하여 2단 터보과급기와 EGR 장치를 장착한 디젤엔진에 대하여 EGR 배열 방식이 EGR율에 미치는 영향을 분석하기 위하여 시뮬레이션을 수행하였다. 이를 위하여 AMESim을 사용하였고 엔진 부품을 위하여 IFP Engine Library를 사용하였다. 고압, 저압, 반저압의 3가지 배열 방식이 고려되었다. 일반적으로 많이 사용되는 고압 방식과 저압 방식의 EGR 배열이 공연비 21에서 각각 6.4%, 10.0%의 EGR율을 보인 반면, 두 방식의 혼합형인 반저압 EGR 배열 방식의 EGR율은 18.0%의 값을 보였다. 따라서 2단 터보과급기와 EGR 장치를 장착한 엔진 설계시 엔진 성능과 유해배출물 발생량의 관점에서 반저압 방식 EGR 시스템이 적절함을 보였다.