• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.336-336
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• 2011

Over the past decades, organic semiconductors have been investigated intensely for their potential in a wide range of optoelectronic device applications since the organic materials have advantages for very light, flexible and low cost device fabrications. In this study, we fabricated small-molecule organic solar cells (OSCs) based on chloro[subphthalocyaninato]boron(III) (SubPc) as an electron donor and $C_{60}$ as an electron acceptor material. Recently SubPc, a cone-shaped molecule with $14{\pi}$-electrons in its aromatic system, has attracted growing attention in small-molecule OSC applications as an electron-donating material for its greater open-circuit voltage (VOC), extinction coefficient and dielectric constant compared to conventional planar metal phthalocyanines. In spite of the power conversion efficiency (PCE) enhancement of small-molecule OSC using SubPc and $C_{60}$, however, the study on the interface between donor-acceptor heterojunction of this system is limited. In this work, SubPc thin films at various thicknesses were deposited by organic molecular beam deposition (OMBD) and the evolution of surface morphology was observed using atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM). We also investigated the influence of film thickness and surface morphology on the PCE of small-molecule OSC devices.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.101.2-101.2
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• 2012

스크린 프린팅 기술은 공정이 단순하고 값이 싸며 대량생산에 용이하기 때문에 결정질 실리콘 태양전지의 전극형성에 널리 사용되고 있다. 스크린 프린팅 기술을 이용한 전면 전극은 일반적으로 은 페이스트 (Ag paste)를 패시배이션 층이 증착 된 실리콘 기판 위에 인쇄를 한 후 고온의 소성 공정을 통하여 형성이 된다. 은 페이스트가 실리콘 에미터 층과 접촉하기 위해서는 패시배이션 층을 뚫고 접촉이 형성 되어야 한다. 이 과정에서 소성 후 은 전극과 실리콘 기판 사이의 계면에는 glass layer가 형성되어 접촉저항을 높이고 태양전지의 직렬 저항을 높이는 인자로 작용한다. 따라서 본 연구는 형성된 은 전극과 실리콘 사이의 계면 특성을 평가하고 glass layer의 두께와 접촉 저항 사이의 관계를 분석하기 위해서 진행되었다. 접촉저항은 trasnfer length method (TLM) 법을 이용하여 측정을 하였고 glass layer의 두께는 field emission scanning electron microscope(FE-SEM)을 이용하여 평가하였다. 또한 glass layer의 두께에 따른 전반적인 태양전지의 특성을 solar simulator, probe station, suns-Voc를 통하여 평가하였다. 결과적으로 glass layer의 두께에 따라서 접촉저항이나 직렬저항이 변화하는 것을 관찰 할 수 있었고 이를 정량적으로 분석하고자 하는 노력이 시도되었다. 이러한 변화는 또한 태양전지의 특성에 영향을 미치는 것을 확인할 수 있었다.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.2
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• pp.95-106
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• 1998

Volatile organic compounds (VOCs) from Ca to C9 were investigated with nine ambient air samples collected in April 26, August 17, 1996 and January 23, 1997 in a Seoul site. On each sampling day, three 2-hr integrated canister samples were collected in early morning, early afternoon and late afternoon, respectively to study temporal . variation of VOCs. Most of VOC species showed diurnal variation with higher concentrations in the early morning and lower concentrations in the afternoon. The concentrations of light alkanes were high, probably due to the emission from liquefied petroleum gas (LPG) and evaporation of gasoline. Especially, the concentration of propane was the highest in the morning samples. The concentrations of propane, ethylene, acetylene, and toluene were prominent in their hydrocarbon groups, respectively. These components were the main source of car exhaust, gasoline evaporization, LPG, or solvent usage.

• Journal of the Korea Safety Management & Science
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• v.14 no.1
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• pp.201-208
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• 2012

Recently the market of the food waste disposer has increased. Therefore, many companies in the development of food garbage disposer has been increasing interest. In this study, we used QFD (Quality Function Development) to find out the quality factors for the development of the food waste disposer reflecting the consumer needs. HOQ (House Of Quality) showing the correlation between consumer characteristic and engineering characteristic was written by investigating the consumer needs based on the consumer complaints and survey. In addition, we generated the CTQ (Critical To Quality) reflecting the weighting of the importance of the parts. As the research result, the important quality factors for the food garbage disposer were the grinding capability, drying, and odor emission features. The crushing motor associated with grinding and dehydration appeared as the most important quality factors among the parts. Second thing was the fan motor associated with odor. The findings will be able to contribute to the development of the food waste disposer reflecting the consumer needs.

• Analytical Science and Technology
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• v.26 no.4
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• pp.268-275
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• 2013

Many kinds of liquid spray products are used in livelihood activities these days. Spray products can be distinguished by the target to be sprayed (like into the air or on human skin (body)). Because human can be exposed to volatile organic compounds (VOC) emitted from spray products, some considerations on safety or hazard of spray products should be needed. In this study, emission characteristics of VOCs were investigated against 10 types of liquid spray products (6 skin spray and 4 air spray products). The concentrations of benzene and toluene were determined by gas chromatography/mass spectrometry (GC/MS) equipped with a thermal desorber (TD). Their average concentrations from 6 skin spray products exhibited$ 5.64{\pm}1.95$ ($mean{\pm}S.D$) and $8.52{\pm}2.89$ ppb(w), respectively. In contrast, those of 4 air spray samples had $7.30{\pm}1.31$ and $7.19{\pm}1.78$ ppb(w), respectively. If liquid contents in spray samples are completely vaporized in one cubic meter (1 m3) after spraying for 10 seconds, their mean concentrations of skin spray products are $31.7{\pm}8.80$ (benzene) and $50.5{\pm}17.1{\mu}g/Sm^3$ (toluene). In contrast, those of air spray products are $24.0{\pm}4.30$ (benzene) and $23.6{\pm}5.83{\mu}g/Sm^3$ (toluene). The estimated concentration levels of benzene from two types of products (31.7 and $24.0{\mu}/Sm^3$) exceeded the Korean atmospheric environmental guideline ($5{\mu}g/Sm^3$). The results of this study thus suggest that some measures should be made to reduce or suppress the contents of VOC in spray products.

• Journal of Korea Port Economic Association
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• v.36 no.3
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• pp.21-38
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• 2020

Currently, in-port emissions are a serious problem in port cities. However, emissions, especially non-greenhouse gases, from the operation of cargo handling equipment (CHE) have received significant attention from scientific circles. This study estimates the amount of emissions from on-land port diesel-powered CHE in the Port of Incheon. With real-time activity data provided by handling equipment operating companies, this research applies an activity-based approach to capture an up-to-date and reliable diesel-powered CHE emissions inventory during 2017. As a result, 105.6 tons of carbon monoxide (CO), 243.2 tons of nitrogen oxide (NOx), 0.005 tons of sulfur oxide (Sox), 22.8 tons of particulate matter (PM), 26.0 tons of volatile organic compounds (VOCs), and 0.2 tons of ammonia (NH3) were released from the landside CHE operation. CO and NOx emissions are the two primary air pollutants from the CHE operation in the Port of Incheon, contributing 87.71% of the total amount of emissions. Cranes, forklifts, tractors, and loaders are the four major sources of pollution in the Port of Incheon, contributing 84.79% of the total in-port CHE emissions. Backward diesel-powered machines equipped in these CHE are identified as a key cause of pollution. Therefore, this estimation emphasizes the significant contribution of diesel CHE to port air pollution and suggests the following green policies should be applied: (1) replacement of old diesel powered CHE by new liquefied natural gas and electric equipment; (2) the use of NOx reduction after-treatment technologies, such as selective catalytic reduction in local ports. In addition, a systematic official national emission inventory preparation method and consecutive annual in-port CHE emission inventories are recommended to compare and evaluate the effectiveness of green policies conducted in the future.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.153-162
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• 2020

Objectives: 3D printing technologies have become widely developed and are increasingly being used for a variety of purposes. Recently, the evaluation of 3D printing operations has been conducted through chamber test studies, and actual workplace studies have yet to be completed. Therefore, the objective of this study was to determine the emission of volatile organic compounds(VOCs), metals, and particles from printing operations at a workplace. This included monitoring conducted at a commercial 3D printing service workplace where the processes involved material extrusion, material jetting, binder jetting, vat photo polymerization, and powder bed fusion. Methods: Area samples were collected with using a Tenax TA tube for VOC emission and MCE filter for metals in the workplace. For particle monitoring, Mini Particle Samplers(MPS) were also placed in the printer, indoor work area, and outdoor area. The objective was to analyze and identify particles' size, morphology, and chemical composition using transmission electron microscopy with energy dispersive spectroscopy(TEM-EDS) in the workplace. Results: The monitoring revealed that the concentration of VOCs and metals generated during the 3D printing process was low. However, it also revealed that within the 3D printing area, the highest concentration of total volatile organic compounds(TVOC) was 4,164 ppb at the vat photopolymerization 3D printing workplace, and the lowest was 148 ppb at the material extrusion 3D printing workplace. For the metals monitoring, chromium, which, is carcinogenic for humans, was detected in the workplace. As a characteristic of the particles, nano-sized particles were also found during the monitoring, but most of them were agglomerated with large and small particles. Conclusions: Based on the monitoring conducted at the commercial 3D printing operation, the results revealed that the concentration of VOCs and metals in the workplace were within Korea's occupational exposure limits. However, due to the emission of nano-sized particles during 3D printing operations, it was recommended that the exposure to VOCs and metals in the workplace should be minimized out of concern for workers' health. It was also shown that the characteristics of particles emitted from 3D printing operations may spread widely within an indoor workplace.

• Analytical Science and Technology
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• v.18 no.4
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• pp.344-354
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• 2005

This study was carried out to evaluate the performance of a small chamber sampling and analytical method for the measurement of total volatile organic compounds (TVOC) and formaldehyde (HCHO) emission from building materials. While VOC was determined by the adsorbent tube sampling and sequential thermal desorption coupled with GC/MSD analysis, formaldehyde sampled with DNPH-silica cartridge was analyzed by HPLC. Wide-range performance criteria such as repeatability, desorption efficiency, emission chamber recovery test, duplicate precision, breakthrough volume and method detection limits were investigated for the evaluation of small chamber method. The overall precision of the small chamber sampling and analytical methods was estimated within 20~30% for target compounds. In conclusion, this study demonstrated that the small chamber sampling and analytical method can be reliably applied for the measurement of building materials pollutants.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.490-501
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• 2022

In this study, the isoprene and terpene emissions from 32 major urban tree species were investigated. We conducted sampling using a dynamic enclosure system between June and July 2021. Seedlings aged < three years were enclosed in a chamber consisting of a 400 L transparent Tedlar bag. The air flow from the outlet of the chamber was sampled using Tenax-filled sorbent tubes under standard conditions (temperature: 30°C; PAR: 1,000 μmol/m²/sec). A thermal desorption gas chromatography/mass spectrometry system was used to analyze the following 38 biogenic volatile organic compounds: isoprene, monoterpenes, sesquiterpenes, oxygenated monoterpenes, and oxygenated sesquiterpenes. Isoprene emitters included Quercus mongolica, Salix koreensis, Robinia pseudoacacia, and Salix chaenomeloides. Monoterpene emitters included Pinus strobus, Cedrela sinensis, and Cercis chinensis. The monoterpene emission profiles were dominated by á-pinene, myrcene, camphene, and limonene. The predominant oxygenated monoterpene and oxygenated sesquiterpene were eucalyptol and caryophyllene oxide, respectively. For all species, the contributions of sesquiterpenes and oxygenated sesquiterpenes were relatively low.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.332-338
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• 2017

The objective of this work was to study the low temperature vacuum adsorption technology applicable to small and medium scale painting plants, which is the main emission source of volatile organic compounds. The low-temperature vacuum swing adsorption (VSA) technology is the way that the adsorbates are removed by reducing pressure at low temperature ($60{\sim}90^{\circ}C$) to compensate disadvantages of the existing thermal swing adsorption (TSA) technology. Commercial activated carbon was used and the absorption and desorption characteristics of toluene, a representative VOCs, were tested on a lab scale. Also based on the lab scale experimental results, a $30m^3min^{-1}$ VSA system was designed and applied to the actual painting factory to assess the applicability of the VSA system in the field. As a result of lab scale experiments, a 2 mm pellet type activated carbon showed higher toluene adsorption capacity than that of using 4 mm pellet type, and was used in a practical scale VSA system. Optimum conditions for desorption experiments were $80{\sim}90^{\circ}C$ and 100 torr. In the practical scale system, the adsorption/desorption cycles were repeated 95 times. As a result, VOCs discharged from the painting factory can be effectively removed upto 98% or more even after repeated adsorption/desorption cycles when using VSA technology indicating potential field applicabilities.