There has been a growing concern about the emissions of formaldehyde and VOCs from automotive interior materials which could have an important impact on the in-vehicle air quality(IVAQ) of automotive vehicles. Many leading automobile manufacturers have now introduced their own specification standards for testing and limiting emissions from products produced by their suppliers. In addition, ISO (International Standard Organization) has been established ISO 12219-1, 2, 3, 4, 5 to determine the emissions of volatile organic compounds from automotive vehicle. The objective of this paper is to compare the area specific emission rates determined from surface emissions testing using the microchamber(MC) in comparison with a 1 m³ emission test chamber(ETC) operated in accordance with ISO 12219-3, ISO 12219-4. Measured emission concentrations in absolute terms were different between Microchamber and 1 m³ chamber. However, qualitative comparison of the chromatograms shows that the Microchamber is able to perform a screening test

This is a study on the distribution of acoustic emission parameters during a burst test for a type-II CNG vehicle fuel tank. A resonant AE sensor with a central frequency of 150 kHz was attached to the composite materials in the center of the fuel tank. The pressure was increased from 30 to 100% of the expected burst pressure and was maintained for 10 minutes at each level. Damage at 70% of expected burst pressure occurred by various damage mechanisms including fiber breakage and delamination, while that of below 60% only occurred by matrix crack initiation and growth. The count, duration and rise time of the AE signal at 60% of the expected burst pressure are distributed below 500, 5000 μs and 300 μs, respectively. Then, at above 70% they increased with pressure by superimposing of individual AE signal generated at a nearby place. These results confirmed that the analysis of the distribution of AE parameters is an effective tool for estimating damage of a CNG fuel tank.

This study deals with the high frequency induction hardening (HF at 850℃, 120kHz & 50kW condition) SM45C steel. (1) The HF specimen, which was tempered at 150℃, did not show any tempering effect. A brittle fracture occurred at rounded area of the tensile specimen. AE (acoustic emission) amplitude distribution showed between 45dB and 60dB. (2) A slip and fracture occurred at the hole area of the HF specimen which was tempered at 300℃. As they pass the yield point, the AE energy is increased intermittently and AE amplitude distribution exists between 70dB and 85dB. In addition, after imposing the maximum tensile load, AE signals showed high amplitude and energy distribution. The AE amplitude showed between 45dB and 70dB. (3) A brittle fracture occurred at HF specimen which was tempered at 450℃ as if it is torn in the direction of 45° on parallel area over the both sides of the tensile specimen, which lead to several peak appeared in AE energy. It was found that the AE amplitude was relatively low and the AE energy was high.

석탄회는 독특한 화학조성과 광물학적 특징을 가지고 있다. 본 연구는 해안가에 위치한 영동화력발전소의 매립 호수에서 배출되는 석탄회와 주변 해수와의 반응에서 토착 미생물이 중금속 용출에 어떤 영향을 미치는지를 알아보았다. 매립 호수의 pH는 6.3-8.5로 나타났다. 본 연구를 위해 매립 호수의 세 지점을 선정하여 각 지점에서 석탄회(0.4 L)와 해수(1.6 L)가 혼합된 세 개의 시료를 채취하였다. 채취한 시료는 각각 120˚C, 2.5기압 환경하에서 멸균 처리하고, 미생물의 활동을 촉진하기 위해 글루코스를 첨가하여 배양하였으며, 나머지 하나는 자연 상태로 60일 동안 보관하면서 박테리아의 활동에 따른 지화학적 변화과정을 살펴보았다. 다른 시료와 비교하여 글루코스를 첨가한 시료에서 15일 후에 알카리도가 크게 증가하였으며, Mg, Ca, K와 같은 양이온은 글루코스를 넣은 시료에서 초기에 증가하다가 15일 이후 감소하였다. SO42-는 글루코스를 첨가한 시료에서 크게 감소하였다. 이러한 지화학적 결과는 매립 호수에 서식하는 박테리아의 활동성과 관련이 있다. 이러한 결과는 석탄회 내에 서식하는 박테리아의 특성을 이해하기 위한 기초자료로서 활용될 수 있을 것으로 판단된다.

A diagnostic tool has been proposed to convert the observed surface distribution of hydrogen recombination line intensities into the radial distributions of the electron temperature and the density in HII regions. The observed line intensity is given by an integral of the volume emission coefficient along the line of sight, which comprises the Abel type integral equation for the volume emission coefficient. As the emission coefficient at a position is determined by the temperature and density of electrons at the position, the local emission coefficient resulted from the solution of the Abel equation gives the radial distribution of the temperature and the density. A test has been done on the feasibility of our diagnostic approach to probing of HII regions. From model calculations of an HII region of pure hydrogen, we have theoretically generated the observed surface brightness of hydrogen recombination line intensities and analyzed them by our diagnostic tool. The resulting temperatures and densities are then compared with the model values. For this case of uniform density, errors in the derived density are not large at all the positions. For the electron temperature, however, the largest errors appear at the central part of the HII region. The errors in the derived temperature decrease with the radial distance, and become negligible in the outer part of the model HII region.

본 연구에서는 원적외선 방출 직불 소재를 개발하기 위해서 나노사이즈 게르마늄 업자와 PET chip을 마스터 배치 칩으로 제조하고 이를 PET와 용융 방사하여 sheath-core conjugate 복합사를 제조하여 이들의 물성과 이들 복합사로 제조한 직물의 원적외선 방출특성을 측정 분석하였다. 또한 게르마늄을 함유한 필라멘트와 직물의 물성을 측정하고 이들 물성이 사가공 공정의 중요공정 인자인 벨트각과 사속비 등의 공정인자와 직물 설계에서의 경사와 위사의 밀도에 관계하는 직물 밀도 계수 등의 설계 조건에 의해 직물 역학 특성과 직물 촉감등의 물성이 어떠한 변화를 가져 오는가에 대한 분석을 하였다. 최적 방사조건에 의한 core부에 게르마늄이 함유된 sheath-core형 PET복합사를 제조하였으며 이들의 절단강신도 모두 일반 PET계(系)의 물성치를 보였으며 DTY는 제직성에 문제가 없는 강신도를 보였고 습건열 수축률은 일반 PET사 보다 높은 값을 보였다. 게르마늄 함유 직물의 원적외선 방사강도는 5~20μm 파장 영역에서 3.53×102W/m2을 보였으며 방사율은 0.874를 보였다. 그리고 최적 사가공 공정 조건 설정과 최적 직물밀도 설계로 직물의 역학 특성치와 촉감 특성의 저하를 막을 수 있음을 확인할 수 있었다.

Attractiveness of different amounts of methyl (E,E,Z)-2,4,6-decatrienoate, the aggregation pheromone of brown-winged stink bug, Plautia stali (Hemiptera: Pentatomidae), was tested using different kinds of dispensers. A lure filled with hexane was used as a control treatment. There were no differences in the attractiveness of the pheromone to P. stali and Halyomorpha halys among dispensers (polyethylene-vial, rubber septum, and polyethylene tube). Traps baited with 7, 20, 40, 50, and 60 ㎎ of pheromone were tested for their attractiveness. For females, the 40 ㎎ trap attracted highest number of P. stali, even though there were no significant differences among pheromone amounts. For males, the 40 and 50 ㎎ traps attracted significantly more bugs than the 7, 20, and 60 ㎎ traps and the control traps. Based on these results, the pheromone dispenser impregnated with 40 ㎎ of pheromone will be practical in monitoring P. stali in the field.

Recent high efficiency electronic devices have been found to have heat emission problems. As for LEDs, an excessive increase in the device temperature causes a drop of the luminous efficiency and circuit lifetime. Therefore, heat release in the limited space of such electronic parts is very important. This is a study of the possibility of using a coating of carbon materials as a solution for the thermal emission problem of electronic devices. Powdered carbon materials, cokes, carbon blacks, amorphous graphite, and natural flakes were coated with an organic binder on an aluminum sheet and the subsequent thermal emissivity was measured with an FT-IR spectrometer and was found to be in the range of 5~20 μm at 50˚C. The emissivity of the carbon materials coated on the aluminum sheet was shown to be over 0.8 and varied according to carbon type. The maximum thermal emissivity on the carbon black coated-aluminum surface was shown to be 0.877. The emissivity of the anodized aluminum sheets that were used as heat releasing materials of the electronic parts was reported to be in the range of 0.7~0.8. Therefore, the use of a coating of carbon material can be a potential solution that facillitates heat dissipation for electronic parts.

Hybridization of semiconductor materials with carbon nanotubes (CNTs) is a recent field of interest in which new nanodevice fabrication and applications are expected. In this work, nanowire type GaAs structures are synthesized on porous single-wall carbon nanotubes (SWCNTs) as templates using the molecular beam epitaxy (MBE) technique. The field emission properties of the as-synthesized products were investigated to suggest their potential applications as cold electron sources, as well. The SWCNT template was synthesized by the arc-discharge method. SWCNT samples were heat-treated at 400˚C under an N2/O2 atmosphere to remove amorphous carbon. After heat treatment, GaAs was grown on the SWCNT template. The growth conditions of the GaAs in the MBE system were set by changing the growth temperatures from 400˚C to 600˚C. The morphology of the GaAs synthesized on the SWCNTs strongly depends on the substrate temperature. Namely, nano-crystalline beads of GaAs are formed on the CNTs under 500˚C, while nanowire structures begin to form on the beads above 600˚C. The crystal qualities of GaAs and SWCNT were examined by X-ray diffraction and Raman spectra. The field emission properties of the synthesized GaAs nanowires were also investigated and a low turn-on field of 2.0 V/μm was achieved. But, the turn-on field was increased in the second and third measurements. It is thought that arsenic atoms were evaporated during the measurement of the field emission.

This study investigated tensile deformation of the stress aging heat-treated SM45C steel which are aging temperature at 250℃ and 300℃; aging time at 1 hour and, 3 hours; applied load at 300N and 400N by using an acoustic emission techniques (AEs). A signal processing technology is applied to evaluate an AE source characterization of different AE measurement systems DiSP & PCI-2. In this study, most suitable aging condition appeared at 250℃, 3 hours and 300N. But in cases of 250℃, 3 hours, 400N and 300℃, 3 hours, 400N conditions, yield load decreased compare to other conditions according to the over-aging phenomena. On the other hand, when arranged via AE amplitude results by K-means clustering pattern recognition of AE raw signals, tendency of signal strength appeared non-heat treatment condition, 'Class 1 < Class 2 < Class 3'; optimal condition, 'Class 3 < Class 2'; over-aging condition, 'Class 3 < Class 2 < Class 1'. This is judged by emitting a lot of AE energy when material causes plastic deformation because ductility increases on factor by over-aging phenomenon.

본 연구에서는 상용코드인 ADINA를 이용하여, 유입풍속과 바람의 입사각을 변화시키며 이중원형실린더에서 발생하는 와류방출 현상과 실린더에 작용하는 공기력의 변동양상을 분석하였다. 본 연구결과 다음과 같은 결과를 얻을 수 있었다. 첫째, 레이놀즈수가 4,970인 경우에는 Karman vortex가 지배적으로 발생하며 레이놀즈수가 331,344인 경우에는 실린더 후면에 폭이 좁은 후류(turbulent wake)가 지배적으로 발생하는데, 이러한 기류현상은 바람의 입사각과 함께 풍하측 실린더에 작용하는 공기력의 비대칭성을 유발하는 원인이 된다. 둘째, 본 연구의 모의조건에서 풍상측과 풍하측 실린더는 거의 동일한 주파수의 와류를 방출하고 있으나, 풍상측과 풍하측 실린더에서 발생하는 와류 간의 위상차는 유입풍속에 따라 변동하는 특성을 보인다.

This study is deal with the high frequency induction hardening (HF at 850℃, 120kHz & 50kW condition) SM45C steel. (1) The HF specimen which was tempered at 150℃, did not appear any tempering effect. A brittle fracture occurred at rounded area of the tensile specimen. AE amplitude distribution showed between 45~60dB. (2) The HF specimen which was tempered at 300℃, slip and fracture occurred at the hole area of the tensile specimen. As it passes the yield point, the AE energy increased intermittently and AE amplitude distribution showed between 70~85dB. In addition, after the maximum tensile load, it showed high amplitude and energy distribution. The AE amplitude showed between 45~70dB. (3) The HF specimen which was tempered at 450℃, a brittle fracture occurred as if it is torn in the direction of 45℃ on parallel area over the both sides of the tensile specimen, which led to several peak to be appeared in AE energy. It was found that the AE amplitude was relatively low and the AE energy was high.