• 한국자동차공학회논문집
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• 제18권3호
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• pp.143-148
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• 2010

In this study, the potential possibility of biodiesel fuel(BDF) and oxygenated fuel(ethylene glycolvmono-n-butyl ether; EGBE) was investigated as an effective method of decreasing the smoke emission. The smoke emission of blending fuel (BDF and EGBE 0~20 vol-%) was reduced in comparison with diesel fuel and it was reduced approximately 64% at 2000 rpm, full load in the 20% of blending rate. But torque and brake specific energy consumption( BSEC) didn't have no large differences. Also, the effects of exhaust gas recirculation(EGR) for the reduction of NOx emission has been investigated. Consequently, It was found that simultaneous reduction of smoke and NOx emission was achieved with BDF(90 vol-%) and EGBE(10 vol-%) blended fuel and cooled EGR method(5~10%).

• 대한한의학방제학회지
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• 제21권1호
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• pp.71-79
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• 2013

Objectives : Yijin-tang has been used in the treatment of gastrointestinal diseases such as irritable bowel syndrome, gastritis, and gastric ulcer. In this study, a high-performance liquid chromatography (HPLC) method was established for simultaneous analysis of six compounds, liquiritin, glycyrrhizin, hesperidin, 6-gingerol, homogentisic acid, and 3,4-dihydroxybenzaldehyde in Yijin-tang, a traditional Korean herbal medicinal preparation. Methods : A Gemini C18 column was used for the separation of six constituents at $40^{\circ}C$. The mobile phase using gradient elution consist of two solvent systems, 1.0% acetic acid in water (A) and 1.0% acetic acid in acetonitrile (B). The flow-rate was 1.0 mL/min and injection volume was $10{\mu}g$. The detector was a photodiode array (PDA) detector set at 254 nm and 280 nm. Results : The calibration curves of six compounds showed good linearity in various concentration ranges ($R^2{\geq}0.9997$). The limits of detection (LOD) and limits of quantification (LOQ) were 0.028-$0.192{\mu}g/mL$ and 0.093-$0.540{\mu}g/mL$, respectively. The RSD (%) of the intra and inter day validations were 0.03-0.84% and 0.05 -1.00%, respectively. Recovery was 96.14-01.90% and RSD (%) was less than 1.5%. Conclusions : The established simultaneous analysis methods will help management to improve the quality of Yijin-tang.

• 대한기계학회논문집B
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• 제27권12호
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• pp.1691-1698
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• 2003

In this paper, the combination effects of oxygen component in fuel and exhaust gas recirculation on the exhaust emissions have been investigated for a direct injection diesel engine. It is a kind of effective oxygenated fuel of diether group that the smoke emission of DGM(diethylene glycol dimethyl ether) blended fuel is reduced remarkably compared with commercial diesel fuel, that is, it can supply oxygen component sufficiently at higher loads and speeds in diesel engine. But, NOx emission of oxygenated fuel was increased compared with commercial diesel fuel. Also, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission has been investigated. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel(DGM 5vol-%) and cooled EGR method(10∼15%).

• 한국자동차공학회논문집
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• 제17권3호
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• pp.62-67
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• 2009

In this study, the potential possibility of biodiesel fuel was investigated as an alternative fuel for a naturally aspirated indirect injection diesel engine. The smoke emission of biodiesel fuel was reduced remarkably in comparison with diesel fuel, that is, it was reduced approximately 36% at 2000rpm, full load condition. And, power, torque and brake specific energy consumption showed no significant differences. However, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel. Also, the effects of exhaust gas recirculation(EGR) to reduce the NOx emission has been investigated. It was found that simultaneous reduction of smoke and NOx was achieved with biodiesel fuel(20vol-%) and cooled EGR method$(10{\sim}15%)$.

• 한국자동차공학회논문집
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• 제3권6호
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• pp.112-122
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• 1995

As an alternative fuel producing less exhaust emissions, natural gas is of interest for use both in SI and CI engines. The potential of natural gas fuelled dual-fuel engine is considered high enough. However, much effort has to be made so that gaseous fuel is used efficiently with simultaneous minimum use of pilot oil. Hence, a simplified three-dimensional model, using a finite volume method in cylindrical coordinates, has been developed to facilitate an understanding of the dual-fuel combustion phenomena and to predict the complex interactions between the pilot distillate and natural gas. The computer model was calibrated by comparing it with the experimental results obtained from diesel engine like combustion bomb tests. In the pre-mixed natural gas combustion, the fuel burning was highly reliant on the injection condition and subsequent burning nature of the pilot distillate.

• Bulletin of the Korean Chemical Society
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• 제15권11호
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• pp.945-949
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• 1994

Mixtures of cyano complexes of palladium(II) and platinum(II) were separated by capillary electrophoresis using a fused silica capillary as a separation column and 30 mM phosphate buffer (pH 7) containing 15 wt. % acetonitrile as a running buffer. By virtue of the high ionic mobilities of the negatively charged cyano complexes of Pd(II) and Pt(II), they were separated using a cathodic injection and anodic detection scheme. The metal complexes eluted through the capillary were detected by direct UV absorption at 214 nm. A linear relationship between peak area and concentration was obtained for both ions and the detection limit was lower than $10^{-14}$ mole. The proposed method was applied to real sample, e.g., anode slime obtained from an electrolytic copper refinary, as a method for the simultaneous determination of palladium and platinum.

• 분석과학
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• 제30권4호
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• pp.194-204
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• 2017

Direct injection (DI) and solid phase extraction (SPE) methods for the simultaneous determination of pendimethalin (PDM) and dinoseb (DNS) in environmental water have been optimized using the ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. The limits of quantification (LOQs) of PDM and DNS were $0.01{\mu}g/L$ using the DI method and $0.0001-0.0002{\mu}g/L$ using the SPE method. The precision by SPE UPLC-MS/MS was less than 11 % for intra-day and inter-day analyses. When the proposed SPE method was used to analyze two analytes in environmental water, PDM was detected in a concentration range of $0.0002-0.011{\mu}g/L$ in 31 samples of the 114 surface water samples, and DNS was detected in a concentration range of $0.0005-0.045{\mu}g/L$ in 17 samples of the 114 surface water samples analyzed. When the DI method was used to analyze target compounds in the same samples, the detected concentrations of the two analytes were within 21% in samples with concentrations above $0.01{\mu}g/L$. The DI UPLC-MS/MS method can thus be used for the routine monitoring of PDM and DNS in environmental water, and the SPE LC-MS/MS method can be used for the determination of the ultra-trace PDM and DNS residues in environmental water.

• 한국수정란이식학회지
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• 제5권2호
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• pp.38-44
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• 1990

This study was carried out to produce superior dairy cattle by embryo transfer. Seven dairy cows were superovulated with divided injection of FSH 4Omg for 5 days started on day 9 to 14 of the estrus cycle and injection of PGF$_2$$\alpha$ 45mg on day 4 of FSH injection. Donor cows were flushed to collect embryos on day 7 or 8 of the estrus cycle. Fresh embryos collected were transferred to synchronized dairy recipients or frozen using glycerol 3 step method to he equilibrated. And 35 embryos which were frozen using glycerol 6 step method were imported from U.S.A. After glycerol dilution of frozen embryos was done by reverse density during freezing. frozen-thawed embryos were transferred to synchronized dairy or beef recipients. The results obtained were as follows; 1. Total of 24 embryos were collected from 7 donor cows flushed and transferable embryos were 18 (75.0%). 2. Among 24 embryos. morula, early blastocyst, blastocyst, expanded blastocyst and unfertilized ova were 3 (12.5%), 1 (4.2%), 10 (41.6%), 4 (16.7%) and 6 (25.0%), respectively. 3. Heat inducing rate after 1st and 2nd injections of PGF$_2$$\alpha$ in Holstein and beef cattle was 83.3% and 71.4% and 62.5% and 69.2%, respectively. 4. Among 56 recipients, 23 head were pregnant (41.1%). The pregnancy rate of fresh embryos was 50.0% (1/2 heads) and the pregnancy rate of frozen embryos which were frozen using glycerol 3 step and using glycerol 6 step imported from U.S.A. was 52.6%(l0/19 heads) and 34.3%(12/35 heads), respectively. 5. The pregnancy rate of blastocyst (60.0%) was higher than that of morula (39.0%), early blastocyst (25.0%) and expanded blastocyst (0%). 6. The pregnancy rate of grade I embryos (52.2%) was higher than that of grade 2 (34.6%) and grade 3 (28.6%). 7. The pregnancy rate according to synchrony of recipient with donor was higher in simultaneous recipient (55.0%) and +l2hrs' (53.8%) than -24hrs' (23.5%), -l2hrs' (20.0%) and +24hrs' (0%).

• Asian Journal of Atmospheric Environment
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• 제11권4호
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• pp.283-299
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• 2017

An analytical method using high-performance liquid chromatography (HPLC) with fluorescence (FL) detection was developed for simultaneously analyzing 10 polycyclic aromatic hydrocarbons (PAHs) and 18 nitro-derivatives of PAHs (NPAHs). The two-dimensional HPLC system consists of an on-line clean-up and reduction for NPAHs in the 1st dimension, and separation of the PAHs and the reduced NPAHs and their FL detection in the 2nd dimension after column-switching. To identify an ideal clean-up column for removing sample matrix that may interfere with detection of the analytes, the characteristics of 8 reversed-phase columns were evaluated. The nitrophenylethyl (NPE)-bonded silica column was selected because of its shorter elution band and larger retention factors of the analytes due to strong dipole-dipole interactions. The amino-substituted PAHs (reduced NPAHs), PAHs and deuterated internal standards were separated on polymeric octadecyl-bonded silica (ODS) columns and by dual-channel detection within 120 min including clean-up and reduction steps. The limits of detection were 0.1-9.2 pg per injection for PAHs and 0.1-140 pg per injection for NPAHs. For validation, the method was applied to analyze crude extracts of fine particulate matter ($PM_{2.5}$) samples and achieved good analytical precision and accuracy. Moreover, the standard reference material (SRM1649b, urban dust) was analyzed by this method and the observed concentrations of PAHs and NPAHs were similar to those in previous reports. Thus, the method developed here-in has the potential to become a standard HPLC-based method, especially for NPAHs.

• 대한예방한의학회지
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• 제17권3호
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• pp.165-176
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• 2013

Objective : The purpose of this study was to establish the simultaneous analysis for six compounds in Gumiganghwal-tang (GMGHT, Jiuweiqianghuo-tang) and to investigate the anti-atherosclerotic effects of GMGHT in vitro. Methods : The column for separation of six compounds was used Luna $C_{18}$ column and maintained at $40^{\circ}C$. The mobile phase for gradient elution consisted of two solvent systems, 1.0% acetic acid in water and 1.0% acetic acid in acetonitrile. The analysis was carried out at a flow rate of 1.0 mL/min with pothodiode array (PDA) detection at 254, 280, and 320 nm. The injection volume was 10 ${\mu}L$. The antioxidant activities of GMGHT were evaluated by measuring free radical scavenging activities on 2,2'-Azinobis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) and 1-1-diphenyl-2-picrylhydrazyl (DPPH). The inhibitory effects on low-density lipoprotein (LDL) oxidation were evaluated by the formation of thiobarbituric acid relative substances (TBARS), relative electrophoretic mobility (REM), and fragmentation of apolipoprotein B (ApoB)-100. Results : Calibration curves were acquired with $r^2{\geq}0.9998$. The contents of liquiritin, ferulic acid, baicalin, baicalein, glycyrrhizin, and wogonin in GMGHT were 1.784, 1.693, 37.899, 0.258, 1.869, and 0.034 mg/g, respectively. The GMGHT showed the radical scavenging activity in a dose-dependent manner. The concentration required for 50% reduction ($RC_{50}$) against ABTS and DPPH radicals were 72.51 ${\mu}g/mL$ and 128.49 ${\mu}g/mL$. Furthermore, GMGHT reduced the oxidation properties of LDL induced by $CuSO_4$. Conclusion : HPLC-PDA is considered as an available and convenient method for quality control and standardization of GMGH and GMGHT has potentials on anti-atherosclerosis by anti-oxidative effect and suppressive effect on LDL oxidation.