• Korean Chemical Engineering Research
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• 제53권1호
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• pp.57-63
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• 2015

본 연구에서는 기-액 평형장치와 반응열 측정장치를 이용하여 2-methylpiperidine (2MPD), 3-methylpiperidine (3MPD), 4-methylpiperidine (4MPD) 흡수제의 이산화탄소 흡수특성을 연구하였다. 기-액 평형장치를 이용하여 각 흡수제의 이산화탄소 흡수능을 알아보았고, 흡수평형 후의 흡수액을 핵자기공명장치(nuclear magnetic resonance spectroscopy: NMR)로 분석하여 종 형성을 확인하였다. 추가적으로 반응열 측정장치를 이용하여 흡수능에 따른 반응열을 제시하였다. 실험결과 2MPD, 3MPD, 4MPD 흡수제는 작용기 위치에 따라 다른 특성을 나타내었다. Ortho 위치에 메틸기를 가진 2MPD는 입체장애효과로 인하여 흡수반응에서 특이성이 나타났으나 3MPD와 4MPD는 ($H_2O$-piperidine-$CO_2$) 시스템에서 반응 특이성이 나타나지 않았다.

• 한국철도학회논문집
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• 제19권2호
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• pp.109-116
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• 2016

고속철도 차량의 시장 점유율은 전 세계적으로 확대되고 있다. 고성능 충격 에너지 흡수 요소는 철도차량의 안전 기준을 충족하는 것이 필수 요소이다. 변형 튜브 조립체는 철도 차량에 대한 전형적인 에너지 흡수 요소이다. 그것은 변형 튜브와 압입 펀치로 구성되어 있으며 튜브 조립체의 성능은 튜브의 소성 영역에서 흡수 에너지 특성에 의존한다. 본 논문의 변형 튜브에서 흡수하는 소성변형 에너지는 200kJ의 철도차량 충돌 에너지를 흡수하도록 설계되어 있다. 슬래브 법과 유한 요소해석을 사용하여 초기 단계에서 펀치의 반력은 예측되며 설계된 튜브 조립체의 성능은 실험으로 확인되었다.

• Structural Engineering and Mechanics
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• 제91권1호
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• pp.75-86
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• 2024

In this paper, the porous metal PM-35 is proposed as the filler material of filled thin-walled tubes (FTTs), and a series of experimental study is conducted to investigate the dynamic behavior and energy absorption performance of PM-35 filled thin-walled tubes under impact loading. Firstly, cylinder solid specimens of PM-35 steel are tested to investigate the impact mechanical behavior by using the Split Hopkinson pressure bar set (SHP); Secondly, the filled thin-walled tube specimens with different geometric parameters are designed and tested to investigate the feasibility of PM-35 steel applied in FTTs by the orthogonal test. According to the results of this research, it is concluded that PM-35 steel is with the excellent characteristics of high energy absorption capacity and low yield strength, which make it a potential filler material for FTTs. The micron-sizes pore structure of PM-35 is the main reason for the macroscopic mechanical behavior of PM-35 steel under impact loading, which makes the material to exhibit greater deformation when subjected to external forces and obviously improve the toughness of the material. In addition, PM-35 steel core-filled thin-wall tube has excellent energy absorption ability under high-speed impact, which shows great application potential in the anti-collision structure facilities of high-speed railway and maglev train. The parameter V0 is most sensitive to the energy absorption of FTT specimens under impact loading, and the sensitivity order of different variations to the energy absorption is loading speed V0>D/t>D/L. The loading efficiency of the FTT is affected by its different geometry, which is mainly determined by the sleeve material and the filling material, which are not sensitive to changes in loading speed V0, D/t and D/L parameters.

• 한국공작기계학회논문집
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• 제15권6호
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• pp.114-120
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• 2006

Front-end side members of vehicles are structures with the greatest energy absorbing capability in a front-end collision of vehicles. This paper was undertaken to analyze the energy absorption characteristics of spot welded hat and double hat-shaped section members under the axial collapse. The experiments were performed with respect to the various collapse velocities. It was expected that para-closed sections would show collapse characteristics which be quite different from those of perfectly closed sections. The collapse velocities were selected as follows: the velocities in the hat-shaped section members were 0.00017m/sec, 0.017m/sec, 4.7m/sec, 6.5m/sec, 6.8m/sec, 7.2m/sec, and 7.3m/sec those in the double hat-shaped section members were 0.00017m/sec, 0.017m/sec, 6.5m/sec, 6.8m/sec, 7.2m/sec 7.3m/sec, and 7.9m/sec. In the program system presented in this study, an explicit finite element code, LS-DYNA3D, is adopted for simulating complicated collapse behavior of the hat and double hat-shaped section members under the same condition of the collapse test. The validity of simulation was confirmed by the comparison between the simulation result and the collapse experiment.

• 방사선산업학회지
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• 제3권1호
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• pp.31-37
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• 2009

This paper describes the preparation of manufacturing a new nanocomposite material, which involves adding a multi walled carbon nanotube (MWCNT) to improve thermal characteristics of poly (ethylene-co-vinyl acetate) (EVA). We irradiated the prepared nanocomposites with doses of 50 kGy, 100 kGy and 200 kGy at a dose rate of $5kGy\;hr^{-1}$ and examined their thermal stability, activation energy and crosslink level by using a thermogravimetric analyzer (TGA) and gel fraction experiments. TGA results indicated that the samples with a MWCNT had higher Derivative Thermo Gravimetry (DTG) 2nd peak temperatures than those without a MWCNT. And activation energy of the samples reduced as the absorption dose and the MWCNT content increased. Finally, the gel fraction increased rapidly up to 100 kGy as total absorption dose increased, and then the growth rate of all samples was slowly increased from 100 kGy.

• 한국정밀공학회지
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• 제17권3호
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• pp.192-199
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• 2000

The spot-welded automotive side member which has a hat-shaped section and a double hat shaped section has been tested on the axial static(10mm/min) and quasi-static(50mm/min) compressing load. The collapse characteristics of automotive sections have been reviews on shift on shape and in width of the spot-voiding on the flange. On the basis of the results of tests and reviews, the optimum energy absorption capacity of the structure has been studied.

• 에너지공학
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• 제17권4호
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• pp.241-246
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• 2008

화석연료 사용에 의한 이산화탄소의 증가는 지구온난화의 주요인으로, 세계적으로 배출량을 줄이려는 노력을 기울이고 있다. 알카놀아민 수용액을 이용한 흡수법은 산성가스를 제거하기 위하여 폭 넓게 사용되고 있고, 특히 배가스로부터 나오는 이산화탄소의 제거에 효과적인 것으로 알려져 있다. 본 연구에서는 알카놀아민 수용액을 사용하여 이산화탄소 흡수시에 나타나는 흡수특성을 연구하였다. 기/액 평형 실험 장치를 사용하여 이산화탄소의 평형분압(${P_{CO_2}}^*$)과 이산화탄소 최초 1회 주입 후 평형에 도달하는 시간을 측정하여 $60^{\circ}C$에서 각각 흡수 용량과 흡수 속도를 계산하였다. 실험 결과 MEA 10wt%에서의 흡수용량은 낮은 온도($40^{\circ}C$)에서 우수하였고, 평형부하 0.5부근에서 이산화탄소가 포화되었음을 알 수 있었다. 흡수제에 따른 흡수용량은 AMP>DEA>MEA, 흡수속도는 MEA>AMP>DEA. 순으로 나타났다. 따라서 가장 우수한 성능을 가진 흡수제를 선정하기 위해서는 흡수용량과 흡수속도를 동시에 고려해보아야 한다.

• 한국수소및신에너지학회논문집
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• 제24권4호
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• pp.334-339
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• 2013

In this study, as a candidate of the carbon dioxide ($CO_2$) absorbents, the mixture solution of polyethylene glycol dimethyl ether (PEGDME) and tetrahydrofuran (THF) were investigated. $CO_2$ absorption rate was measured by using high pressure $CO_2$ screening equipment in the range of 1 - 10wt% THF. Absorption capacity of the mixture solution was also estimated. Based on the results, we found that mixture solution containing THF had higher absorption rate and $CO_2$ loading capacity compared to PEGDME at $25^{\circ}C$.

• Current Photovoltaic Research
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• 제4권3호
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• pp.93-97
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• 2016

Light-emitting chromophores have been separated from silica spheres modified the surface with 3-(trimethoxysilyl)propylmethacrylate (TMSPM). The photoluminescence characteristics of the chromophores were investigated with various excitation wavelengths. The TMSPM was attached to the surface of silica spheres at $75^{\circ}C$. Large number of round shaped particles of the TMSPM was on the surface of silica spheres after 3 h reaction. The TMPSM was completely covered on the surface of the spheres after 6 h reaction. The surface modified silica spheres were soaked into acetone and stored for 20 days at ambient condition. The solution color slowly changed from light yellow to deep yellow with the increase of the storing time. The FTIR absorption peaks at 3348, 2869, 2927, 1715, 1453/1377, 1296, and $1120cm^{-1}$ represent C-OH, $R-CH_3$, $R_2-CH_2$, -C=O, C-H, C=C-H, and Si-O-Si absorption, respectively. The FTIR absorption peak at $1715cm^{-1}$ representing the ester -C=O stretching vibration for silica spheres stored for 20 days was increased compared with the spheres without aging. The UV-visible absorption peaks were at 4.51 eV (275 nm) and 3.91 eV (317 nm). There were two luminescence peaks at 2.51 eV (495 nm) and 2.25 eV (550 nm). The emission at 2.51 eV was dominant peak when the excitation energy was higher than 2.58 eV, and emission at 2.25 eV became dominant peak when the excitation energy was lower than 2.58 eV.

• 한국생산제조학회지
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• 제21권6호
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• pp.865-870
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• 2012

CFRP of the advanced composite materials as structure materials for vehicles has a widely application in lightweight structural materials of air planes, ships and automobiles because of high strength and stiffness compared with conventional materials. This study is to investigate the energy absorption characteristics and collapse mode of CFRP single and double hat shaped structural member under the axial static collapse test. The CFRP single and double hat shaped structural members stacked at different angles (${\pm}15^{\circ}$, ${\pm}45^{\circ}$, ${\pm}90^{\circ}$, $90^{\circ}/0^{\circ}$ and $0^{\circ}/90^{\circ}$ where the direction on $0^{\circ}$ coincides with the axis of the member). The axial static collapse tests were carried out for each member. Collapse mode and energy absorption characteristics of the each member were analyzed.