DPF 장착 경유승용차의 재생시 미세입자 배출특성 연구

권상일(Sang-Il Kwon),김종춘(Jong-Choon Kim),박용희(Yong-Hee Park),이창식(Chang-Sik Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Nano-Particles is main subject in health effect. The relationships between transient vehicle operation and nano-particle emissions are not well-known, especially for diesel passenger vehicle with DPF. In this study, a diesel passenger vehicles were measured on a chassis dynamometer test bench with and without DPF regeneration. The particulate matter (PM) emissions of these vehicles were investigated by number, size and mass measurement. The mass of the total PM was evaluated using the standard gravimetric measurement method, the total number and size concentrations were measured on a NEDC driving cycle using Condensation Particle Counter (CPC) and EEPS. Total number concentration by CPC was 1.5×10¹¹N/㎞ and was 20% of result by EEPS. This means about 80% of total particle emission is compromise of volatile and small-size particle(<22㎚). In regeneration, particle emission was 6.2×10¹²N/㎞ and was emitted 400 times compared to without regeneration. and particle of 22~100㎚ size was emitted mainly, showed peak value nearby 40㎚ size. This means regeneration decreased mean size of particle. In before and after regeneration, PM showed no change but particle number showed about 6 times difference. The regeneration influence on particle number emissions is believed to be related to DPF-fill state and filtration efficiency.

Characterization of metal-bearing diesel nanoparticles using single-particle mass spectrometry

Lee, D.,Miller, A.,Kittelson, D.,Zachariah, M.R. Elsevier 2006 Journal of aerosol science Vol.37 No.1

<P><B>Abstract</B></P><P>Acute and chronic health effects have been associated with diesel particulate matter (DPM). Since both ultrafine particles and metals have been implicated in this correlation, we are conducting investigations to characterize the metal content of diesel nanoparticles. For this study, DPM was generated by a 1.5l engine and ferrocene was added to the fuel to raise the level of metal in the system. The exhaust particles were analyzed in real time using a recently developed single-particle mass spectrometer (SPMS) that has the capability of ablating each particle down to its elemental constituents, thereby yielding the relative mass of elements in each particle. Particle-size calibration of the instrument was achieved by correlating the SPMS signal intensity with measured DPM size. Using this approach, we present size- and composition-resolved elemental species distributions for both the nuclei mode and ultrafine portion of the accumulation mode of DPM. Results show that when the fuel is doped with ferrocene, iron-rich nanoparticles are formed and their number and size increase with level of doping. Larger iron-bearing particles are also formed, but it is observed that the metal to carbon ratios increase for smaller particle sizes. Hydrogen to carbon ratios were measured as a function of particle size, which allowed us to determine the relative amounts of organic carbon and elemental carbon in the particles and showed that the hydrogen to carbon ratios increase for smaller sized particles. The combined results are used to discuss the effects of metal doping level and engine load on particle nucleation and mechanisms of DPM formation.</P>

Evaluation of the time-resolved nanoparticle emissions and the vehicle performance characteristics for a turbocharged gasoline direct-injection vehicle with a metal-foam gasoline particulate filter

Baek, Sungha,Jin, Dongyoung,Jang, Wonwook,Myung, Cha-Lee,Park, Simsoo,Lee, Jeongmin Professional Engineering Publishing Ltd 2016 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>The nanoparticle emissions from gasoline direct-injection engines are of concern because of the high particle number concentrations compared with those from a gasoline port fuel injection engine. A gasoline particulate filter is a potential solution for reducing the particulate matter emissions. In this study, a 2.0 l turbocharged gasoline direct-injection vehicle with a metal-foam-type gasoline particulate filter was tested using the New European Driving Cycle and steady vehicle operating conditions. The particle number concentration, the particle-size distribution and the filtration efficiency were determined using a condensation particle counter and a fast response differential mobility spectrometer (DMS500). The particle number emissions (particle numbers per vehicle travelling distance (particles/km)) over the New European Driving Cycle were 1.95x10(12) particles/km for a base vehicle equipped with a three-way catalytic converter and 5.68x10(11) particles/km for the additional installation of a gasoline particulate filter on the base gasoline direct-injection vehicle. The filtration efficiency of the particle number and the particulate matter mass reached approximately 71% and 67% respectively. The nucleation-mode particles in the size range less than 23nm for the gasoline direct-injection vehicle equipped with a three-way catalytic converter were further reduced on installation of a gasoline particulate filter at the downstream position of the three-way catalytic converter. A sharp pressure drop between the gasoline particulate filter of 21.0 mbar was obtained at a vehicle speed of 120km/h in the New European Driving Cycle. The exhaust gas temperature before the gasoline particulate filter reached around 380-610 degrees C at steady vehicle speeds of 60-120km/h. The installation of the gasoline particulate filter has the potential to satisfy the Euro 6c particle number emissions regulations for light-duty gasoline direct-injection vehicles.</P>

Learning Progression을 적용한 중,고등학생의 "물질의 입자성"에 관한 지식과 미시적 표상에 대한 특성 분석

신남수 ( Nam Soo Shin ),고은정 ( Eun Jung Koh ),최취임 ( Chui Lm Choi ),정대홍 ( Dae Hong Jeong ) 한국과학교육학회 2014 한국과학교육학회지 Vol.34 No.5

Learning Progressions(학습진행과정, 이하 LP)은 "과학의 핵심 아이디어(core idea) 혹은 과학 활동(scientific practices) 이해 과정을 상대적으로 단순한 체계에서 전문가의 지식체계로 논리적이고, 순차적인 단계로 정교하게 설명한 틀"로서, 한 교과 내 및 다른 과학영역들 (물리, 지구과학, 생물, 화학)과 연결하여 연계적 교육과정을 구성하는 이론적 기반을 제공한다. 학습은 개개인의 선지식, 선경험, 교과교육과정, 교육과정 등의 여러 요소에 영향을 받는 복잡한 이해 과정으로, LP 단계를 모든 학생들이 동일하게 이동하지 않는다. 학생과 학습환경의 특성에 따른 이동 가능한 학습경로의 서술을 위해서는 다양한 학생 데이터의 수집과 분석이 필요하다. 이러한 과정을 통해서 가설의 LP는 과학적으로 증명된 LP로 규명되며. 비로소 교과과정 개발의 틀(framework)로 역할을 할 수 있다. 본 연구는 미시간 대학 연구팀이 개발한 "물질의 본성(nature of matter)" 주요 개념에서, 하위개념인 "물질의 입자성(particule nature of matter)과 입자적 표상(submicroscophic representation)"의 LP와 관련 평가지를 우리나라 과학교육과정과 연계, 수정하여 개발하였다. 수정된 평가지와 LP는 124명의 중고등학생의 LP 경로 특성을 분석하는데 사용되었다. 학생들의 입자적 개념과 표상의 이해도, 개념과 표상 이해도 연관성을 중점으로 분석하여 관련 과학교육과정과 현장 수업의 문제점과 시사점을 도출하였다. 본 연구결과를 종합해 보면, 높은 레벨 문항의 정답을 고른 빈도수는 낮은 레벨 문항을 모두 정답으로 고른 경우에 높았으며 이는 학생들이 본 연구팀이 개발한 LP 경로로 이해과정을 정교화시킴을 알 수 있다. 하지만, 대부분의 학생들, 특히 고등학생들은 초등학교 수준의 거시적 물질의 본성 개념 LP 단계에 머물고 있으며, 중학교 수준인 미시적 표상 LP 단계에 있다. 입자적 개념과 표상 이해 실패의 주요 원인은 1) 과학적 모델의 본질, 2) 관련 선지식, 3) 미립자 표상의 이해부족으로 정리된다. 본 연구결과는 물질의 입자성과 관련된 개념, 과학활동(특히 모델링)을 증진시키고 개개인 특성에 맞는 맞춤형 학습환경 제공을 위한 학습, 교수, 평가자료 개발에 기여하는 바가 크다. 더 나아가 ``물질의 본성``에 대한 LP연구와 과학적 소양 증진에 긍정적 역할을 할 것으로 기대한다. Learning progressions (LP), which describe how students may develop more sophisticated understanding over a defined period of time, can inform the design of instructional materials and assessment by providing a coherent, systematic measure of what can be regarded as "level appropriate." We developed LPs for the nature of matter for grades K-16. In order to empirically test Korean students, we revised one of the constructs and associated assessment items based on Korean National Science Standards. The assessment was administered to 124 Korean secondary students to measure their knowledge and submicroscopic representations, and to assign them to a level of learning progression for the particle nature of matter. We characterized the level of students`` understanding and models of the particle nature of matter, and described how students interpret various representations of atoms and molecules to explain scientific phenomena. The results revealed that students have difficulties in understanding the relationship between the macroscopic and molecular levels of phenomena, even in high school science. Their difficulties may be attributed to a limited understanding of scientific modeling, a lack of understanding of the models used to represent the particle nature of matter, or limited understanding of the structure of matter. This work will inform assessment and curriculum materials development related to the fundamental relationship between macroscopic, observed phenomena and the behavior of atoms and molecules, and can be used to create individualized learning environments. In addition, the results contribute to scientific research literature on learning progressions on the nature of matter.

누가 암흑물질을 주문했나?: 암흑물질의 필요성

박성찬 한국물리학회 2016 새물리 Vol.66 No.8

Dark matter is a component of matter in the Universe, whose existence is apparent only via gravitational interactions, not via electromagnetic interactions. The amount of dark matter in the energy budget of the Universe is about five times larger than that of the baryonic component in the standard model, but its origin is still not understood. So in this article, we discuss various astrophysical phenomena, virial motion of stars, the flat rotation curve of galaxies, weak gravitational lensing and cosmic microwave background radiation, which clearly show the effects of dark matter and provide theoretical opportunities to explain it. 암흑물질은 중력적으로 그 존재가 드러났으나, 그 이외의 다른 상호작용, 특히 전자기적 상호작용을 통해서는 그 존재가 드러나지 않은 우주의 물질 성분이다. 암흑물질이 차지하는 우주의 에너지 성분은 표준모형이 설명하는 바리온 양에 비해 대략 다섯배에 해당하며 우주의 팽창과 구조 형성에 대단히 중요한 역할을 하지만 그 기원에 대해서는 이해가 부족하다. 본 문에서는 다양한 천체물리학적 현상 중 천체의 비리얼 운동, 은하 회전 곡선, 중력 렌즈 효과, 우주배경복사 등을 통해 나타난 암흑물질의 관측적 증거를 일별하고, 암흑물질의 이론적 가능성에 대해 논의한다.

Computational Science-based Research on Dark Matter at KISTI

조기현 한국우주과학회 2017 Journal of Astronomy and Space Sciences Vol.34 No.2

The Standard Model of particle physics was established after discovery of the Higgs boson. However, little is known about dark matter, which has mass and constitutes approximately five times the number of standard model particles in space. The cross-section of dark matter is much smaller than that of the existing Standard Model, and the range of the predicted mass is wide, from a few eV to several PeV. Therefore, massive amounts of astronomical, accelerator, and simulation data are required to study dark matter, and efficient processing of these data is vital. Computational science, which can combine experiments, theory, and simulation, is thus necessary for dark matter research. A computational science and deep learning-based dark matter research platform is suggested for enhanced coverage and sharing of data. Such an approach can efficiently add to our existing knowledge on the mystery of dark matter.

대형디젤엔진용 Metal Foam Filter의 미세입자 특성

송호영(Hoyoung Song),이민호,김재권(Jaigueon Kim),정충섭(Choongsub Jung),박만호(Manho Park),이정민(Jungmin Lee) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

Fine particles have the greatest demonstrated impact on human health. Their small size allows them to get deep into the lungs and from there they can reach or trigger inflammation in the lung, blood vessels or the heart, and perhaps other organs. Recently many studies have been performed about fine particles, specially nano particle less than 100㎚ size. In this study, we have performed experimental study on SFC reduction characteristics of emission, specially PM and PN(nano particle) and confirmed whether SFC have an advantage of reduction of particulate matter. EEPS measured the sample gas directly extracted from the tailpipe and used first dilutor between tailpipe and EEPS. We found that SFC reduced PM about 49% and PN about 62% and have a high reduction performance of nano particles.

바이오디젤 사용에 따른 경유승용차의 미세입자 배출특성 연구

권상일(Sang-Il Kwon),김종춘(Jong-Choon Kim),박용희(Yong-Hee Park),임철수(Cheol-Soo Lim) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

Recently, lots of researchers have been attracted to develope various alternative fuels and to use renewable fuels as a solution of environmental problems from automobile. and nano-Particles is main subject in health effect. The relationships between transient vehicle operation and nano-particle emissions are not well-known, especially for using biodiesel fuel. In this study, we have been performed experimental test for the exhaust emission and nano particle reduction characteristics by mixed ratio of biodiesel and analyzed the regulated biodiesel components. The particulate matter (PM) emissions were investigated by number and mass measurement. The mass of the total PM was evaluated using the standard gravimetric measurement method, the total number concentrations were measured on a ECE 15+EUDC driving cycle using Condensation Particle Counter (CPC). Total PM was reduced 2 -38% and number concentration was reduced ]-27% by mixed ratio of biodiesel. Total PM was reduced more than particle because volatile particle was measured in Total PM but was not measured in particle.

Discrimination of Charged Particles in a Neutral Beam Line by Using a Solid Scintillation Detector

우종관,고재우,Dong Liu 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.2

In the past several decades, many studies have been conducted to search for non-baryonic dark matter, such as weakly interactive massive particles (WIMPs). In the search for WIMPs, charged particles incident on the detector are background particles because WIMPs are neutral. Charged particles originate from various sources, such as cosmic rays and laboratory materials surrounding the main detector. Therefore, a veto that discriminates charged particles can improve the particledetection efficiency of the entire experiment for detecting WIMPs. Here, we investigate in the thickness range of 1 mm to 5 mm, the optimal thickness of a polystyrene scintillator as a chargedparticle veto detector. We found that 3-mm-thick polystyrene provides the best performance to veto charged particles and the charged-particle background in the search for the WIMP signal. Furthermore, we fabricated 3-mm-thick and 5-mm-thick polystyrene charged particle veto detectors that will be used in an underground laboratory in the search for WIMP dark matter. After exposing those detectors are the actual beam line, we compared the rate of charged particles measured using those detectors and the rate simulated through a Monte Carlo simulation.

Identifying Suspended Particulate Matters in an Urban Coastal System

Jong Ho Ahn 대한환경공학회 2012 Environmental Engineering Research Vol.17 No.3

In situ particle size spectra are obtained from two sequent cruises in order to evaluate the physical consequences of suspended particulate matters caused by episodic storm runoff from the Santa Ana River watershed, an urbanized coastal watershed. Suspended particles from various sources including surface runoff, near-bed resuspension, and phytoplankton are identified in empirical orthogonal function (EOF) analysis and an entropy-based parameterization (Shannon entropy). The first EOF mode is associated with high turbidity and fine particles as indicated by the elevated beam attenuation near the Santa Ana River and Newport Bay outlets, and the second EOF mode explains the suspended sediment dispersal and particle coarsening at the near-surface plume. Chlorophyll particles are also distinguished by negative magnitudes of the first EOF mode, which is supported by the relationship between fluorescence and beam attenuation. The integrated observation between the first EOF mode and the Shannon entropy index accentuates the characteristics of two different structures and/or sources of sediment particles; the near-surface plumes are originated from runoff water outflow, while the near-bottom particles are resuspended due to increased wave heights or mobilizing bottom turbidity currents. In a coastal pollution context, these methods may offer useful means of characterizing particle-associated pollutants for purposes of source tracking and environmental interpretation.