• Journal of Institute of Convergence Technology
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• v.8 no.1
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• pp.5-8
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• 2018

Emissions of diesel vehicles have been regulated by NEDC mode for a long time. However, the NEDC mode has been known the control of emission reduction is not reflected properly on actual road conditions. For these reasons, diesel vehicle emissions are regulated in both NEDC mode and WLTC mode from 2017 to 2020, from 2020 onwards, the emissions of diesel vehicles will measure in WLTC mode only and will not be able to exceed 1.5 times the regulated value. The purpose of this study is to analyze the development trend of diesel vehicle after-treatment system in order to comply with the future regulations on diesel vehicle. As a result, it is essential to reduce the NOx emissions of diesel vehicles for Euro 6, the NOx emissions of the test vehicle equipped with SCR were 30% to 50% loss than the test vehicle equipped with LNT despite the higher curb weight and engine displacement.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.5
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• pp.85-90
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• 2010

As the environmental regulation of vehicle emission is strengthened, investigations for $NO_x$ and PM reduction strategies are popularly conducted. Two current available technologies for continuous $NO_x$ reduction onboard diesel vehicles are Selective Catalytic Reduction (SCR) using aqueous urea and lean $NO_x$ trap (LNT) catalysts. The experiments were conducted to investigate the $NO_x$ reduction performance of SCR system which can control the ratio of $NO/NO_2$, temperature and SV(space velocity), and the model gas was used which is similar to a diesel exhaust gas. The maximum reduction efficiency is indicated when the $NO:NO_2$ ratio is 1:1 and the SV is 30,000 $h^{-1}$ in $300^{\circ}C$. Generally, ammonia slip from SCR reactors are rooted to incomplete conversion of $NH_3$ over the SCR. In this research, slip was occurred in 6cases (except low SV and $NO:NO_2$ ratio is 1:1) after SCR. Among 6 case of slip occurrence, the maximum conversion efficiency is observed when SV is 60,000 $h^{-1}$ in $400^{\circ}C$.

• Journal of Power System Engineering
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• v.20 no.6
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• pp.93-98
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• 2016

Environmental problems are issued throughout all over the world and which are needed the strength management. In case of the diesel cars are also being developing and studying continuously about various after-treatments device such as EGR, LNT, SCR, DPF and DOC etc. which are used for decreasing $NO_X$ and PM. The air temperature goes up to $39^{\circ}C$ in summer and goes down to $-20^{\circ}C$ in winter because of the location. These changing of the temperature can effect to the engine and harmful exhaust gas discharged and it seems to make the increase - decrease different. The result of the evaluate while changing between the test-mode and the air temperature, which expresses that WLTC-mode is 2.2 times and FTP_75 mode is 4.1~6 times increase to the comparison NEDC-mode of the current regulation. The exhaust characteristic of $NO_X$ by the changing temperature increases in the low temperature and 4.3 times in $14^{\circ}C$ and 21.3 times in $-7^{\circ}C$ with maximum when it compares to $23^{\circ}C$. The fuel efficiency of the different weight car and engine with same data is about 5.7 % in maximum.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.6
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• pp.562-572
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• 2015

$NO_x$ emissions from diesel vehicles have been regarded as a main cause of high $NO_2$ concentration in metropolitan area. Recent studies have shown that the on-road $NO_x$ emissions of diesel vehicles are quite higher than the emission limits specified with the pre-defined test method for emission certification. To reduce air pollutants effectively, the discrepancy of emissions in certification and real-driving conditions should be tackled. In this study, the real-driving emissions have been estimated with portable emission measurement system (PEMS). The results of this study have shown that the on-road $NO_x$ emissions from diesel vehicles have been decreased as the introduction of stricter emission regulation, EURO-6, but additional reduction should be still required and robust technologies should be applied to control $NO_x$ in real-driving conditions. RDE-LDV (Real Driving Emission - Light Duty Vehicles) test method being developed in the European Union can represent excessive on-road $NO_x$ emissions of diesel vehicles as applied emission technologies and can be a solution to remove discrepant $NO_x$ emissions between certification and Korean real-driving conditions. Among the $NO_x$ reduction technologies for EURO-6 diesel vehicles, selective catalytic reduction (SCR) system has shown the better performance than lean $NO_x$ trap (LNT) system to control on-road $NO_x$ emissions. Implementing RDE-LDV will require vehicle manufacturers to adopt the more effective $NO_x$ reduction technology in real driving conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.4
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• pp.454-462
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• 2016

This study was conducted in order to estimate the exhaust emissions analysis method of the real driving emission(RDE). The Association for Emissions Control by Catalyst(AECC) has developed a test procedure by using a random cycle method based on the chassis dynamometer. In order to confirm this approach in Korea, Euro 5(DPF), Euro 6(DPF + LNT), and Euro 6(DPF + SCR) were performed on three different vehicles to determine the exhaust gas characteristics of the random cycle, real-road driving test(PEMS), and emission certification driving mode(NEDC). Six different random cycle driving modes were generated by the vehicle specifications(e.g. curb weight, engine power, gear ratio, and maximum acceleration). The NOx emissions were increased in the NEDC, random cycle, and PEMS order in this study regardless of the test vehicles. The random cycle method has the advantage because it utilizes a chassis dynamometer in the laboratories for a repeatable data collection, and it allows any eminent emission improvement checked prior to a real-road driving test with PEMS.

• Animal cells and systems
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• v.1 no.1
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• pp.77-80
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• 1997

DOantrolene is a primary specific therapeutic drug for prevention and treatment of malignant hyperthermia symptoms. The mechanisms underlying the therapeutic effects of the drug are not well understood. The present study aimed at the characterization of the effects of azumolene, a water soluble dantrolene analogue, on ryanodine binding to sarcoplasmic reticulum (SR) from normal and malign::lnt hyperthermia susceptible (MHS) swine muscles. Characteristics of $[^3H]ryanodine$ binding were clearly different between the two types of SR. Kinetic analysis of eH]ryanodine binding to SR in the presence of $2{\mu}M$ $Ca^{2+}$ showed that association constant $(K_{ryanodine}_7$ is significantly higher in MHS than normal muscle SR $(2.83 vs. 1.32{\times}10^7 M^{-1}$, whereas the maximal ryanodine binding capacity $(B_{max})$ is similar between the two types of SR. Addition of azumolene $(e.g. 400{\mu}M)$ did not significantly alter both $K_{ryanodine}$ and $B_{max}$ of $[^3H]$ryanodine binding in both types of SR, indicating that the azumolene effect was not on the ryanodine binding sites. Addition of caffeine activated $[^3H]$ ryanodine binding in both types of SR, and caffeine sensitivity was significantly higher in MHS muscle SR than normal muscle SR $(K_{caffeine}:3.24 vs. 0.82 {\times} 10^2 M^{-l}). Addition of azumolene $(e.g.400{\mu}M)$ decreased Kcaffeine without significant change in $B_{max}$ in both types of SR suggesting that azumolene competes with caffeine binding site(s). These results suggest that malignant hyperthermia symptoms are caused at least in part by greater sensitivity of the MHS muscle SR to the $Ca^{2+}$ release drug(s), and that azumolene can reverse the symptoms by reducing the drug affinity to $Ca^{2+}$ release channels.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.26 no.5
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• pp.266-276
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• 2023

Purpose: Human milk oligosaccharides (HMOs) may be genetically determined based on the secretor and Lewis status of the mother. This study aims to determine the HMO profile and the secretor and Lewis gene status of Indonesian lactating mothers. Methods: Baseline data of 120 mother-infant pairs between 0-4 months post-partum obtained from a prospective longitudinal study was used. The concentrations of 2'-fucosyllactose (2'FL), lacto-N-fucopentaose I (LNFP I), lacto-N-tetraose (LNT), lacto-N-neotetraose (LNnT), 3'-sialyllactose (3'SL), and 6'-sialyllactose (6'SL) were measured. Genetic analysis was performed for mothers using targeted next-generation sequencing and Sanger sequencing. Wild-type AA with the rs1047781 (A385T) polymorphism was categorized as secretor positive, while heterozygous mutant AT was classified as a weak secretor. The presence of rs28362459 (T59G) heterozygous mutant AC and rs3745635 (G508A) heterozygous mutant CT genes indicated a Lewis negative status, and the absence of these genes indicated a positive status. Subsequently, breast milk was classified into various groups, namely Group 1: Secretor+Lewis+ (Se+Le+), Group 2: Secretor-Lewis+ (Se-Le+), Group 3: Secretor+Lewis-(Se+Le-), and Group 4: Secretor-Lewis- (Se-Le-). Data were analyzed using the Mann-Whitney and Kruskal-Wallis rank tests, and a p-value of 0.05 indicated statistical significance. Results: A total of 58.3% and 41.7% of the samples had positive and weak secretor statuses, respectively. The proportion of those in Group 1 was 85%, while 15% were Group 3. The results showed that only 2'FL significantly differed according to the secretor status (p-value=0.018). Conclusion: All Indonesian lactating mothers in this study were secretor positive, and most of them had a Lewis-positive status.

• Journal of the Korea Society of Computer and Information
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• v.16 no.10
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• pp.101-109
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• 2011

The Riemann's zeta function $\zeta(s)$ has been known as answer for a number of primes $\pi$(x) less than given number x. In prime number theorem, there are another approximation function $\frac{x}{lnx}$,Li(x), and R(x). The error about $\pi$(x) is R(x) < Li(x) < $\frac{x}{lnx}$. The logarithmic integral function is Li(x) = $\int_{2}^{x}\frac{1}{lnt}dt$ ~ $\frac{x}{lnx}\sum\limits_{k=0}^{\infty}\frac{k!}{(lnx)^k}=\frac{x}{lnx}(1+\frac{1!}{(lnx)^1}+\frac{2!}{(lnx)^2}+\cdots)$. This paper shows that the $\pi$(x) can be represent with finite Li(x), and presents generalized prime counting function $\sqrt{{\alpha}x}{\pm}{\beta}$. Firstly, the $\pi$(x) can be represent to $Li_3(x)=\frac{x}{lnx}(\sum\limits_{t=0}^{{\alpha}}\frac{k!}{(lnx)^k}{\pm}{\beta})$ and $Li_4(x)=\lfloor\frac{x}{lnx}(1+{\alpha}\frac{k!}{(lnx)^k}{\pm}{\beta})}k\geq2$ such that $0{\leq}t{\leq}2k$. Then, $Li_3$(x) is adjusted by $\pi(x){\simeq}Li_3(x)$ with ${\alpha}$ and error compensation value ${\beta}$. As a results, this paper get the $Li_3(x)=Li_4(x)=\pi(x)$ for $x=10^k$. Then, this paper suggests a generalized function $\pi(x)=\sqrt{{\alpha}x}{\pm}{\beta}$. The $\pi(x)=\sqrt{{\alpha}x}{\pm}{\beta}$ function superior than Riemann's zeta function in representation of prime counting.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.525-531
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• 2011

Exhaust gas recirculation (EGR) is more effective than selective catalytic reduction (SCR) or lean $NO_x$ trap (LNT) for the reduction of $NO_x$ emissions in diesel engines. A large amount of EGR gas is necessary to satisfy the stringent regulations on $NO_x$ emissions. Low pressure loop (LPL) EGR is almost independent of the variable geometry turbocharger (VGT) at a specific boost pressure, so LPL EGR is better than conventional high pressure loop (HPL) EGR in terms of EGR supply. We compare the influence of HPL EGR and LPL EGR on the combustion characteristics at a constant boost pressure in a diesel engine. The dilution ratio was employed as an independent parameter to analyze the effect of the dilution of the intake charge for each EGR loop. At the same level of $NO_x$ emissions, the fuel consumption and smoke opacity were slightly lower for LPL EGR than for HPL EGR.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.217-224
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• 2012

In general, transportation sources include both on-road vehicles and off-road equipment. Off-road vehicles have usually used diesel engines, which have the disadvantage of high NOx emission. Common rail direct injection (CRDI) and after-treatment systems have been applied to meet the exhaust gas emission regulations for diesel vehicles. In the present, agricultural machinery has satisfied the Tier 3 emission regulations by using waste gate turbocharger (WGT) and internal exhaust gas recirculation (EGR). In this paper, the combustion and emission characteristics of an EGR system applied to a 56kW off-road vehicle in non-road transient cycle (NRTC) mode have been investigated. The EGR map was made from foundation experiments determining the EGR duty for all engine operating conditions, and then this map was applied to the NRTC mode. Consequently, the NOx emission was reduced by the EGR system, and the Tier 4 interim emission regulations were satisfied by using both the EGR system and an after-treatment system.