• 한국대기환경학회지
• /
• 제11권4호
• /
• pp.323-329
• /
• 1995

The number of motor vehicles in Korea has increased to about 4 million, and the exhaust gases of these vehicles have become a more threatening factor to public health. Traffic policemen are one of the highest health risk groups since they work on roadsides where they are exposed to high levels of air pollutants. The health effects on them due to air pollution were determined by measuring personal carbon monoxide(CO) exposure and carboxyhemoglobin(COHb) level in blood. Thirty-one traffic policemen in Seoul volunteered to be subjects of the study. In October 1992, personal CO exposure was measured by a CO passive sampler. The subjects wore the CO passive sampler for 8 hours while on duty. The exposed samples were analyzed by gas chromatography. Blood samples from each subject were collected just after the exposure sampling, and were analyzed within 3 hours of blood collection by a CO-oximeter. The activities of the subjects were recorded by the subject in 30 minute intervals using an activity log sheet containing location and time spent. Personal CO exposure were ranged between 0.1 and 14.5ppm, eith an average of 5.9ppm. Carboxyhemoglobin levels ranged from 1.1% to 6.9%, with an average of 3.6%. policemen on duty outdoors had significantly higher CO exposures and COHb levels than policemen on duty indoors(p<0.01). Personal CO exposure and COHb were positively correlated, although the coefficient was not significant. The relationship between CO level and COHb level was confounded by smoking status. Among smokers, COHb level was significantly higher as CO exposure and hours worked outdoors increased.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제16권1호
• /
• pp.41-47
• /
• 2016

Purpose: The purpose of this study was to evaluate electrical and structural degradation of flexible CIGS sollar cell exposed to high temperature and humid atmosphere. Method: Accelerated degradation was performed for various time under $85^{\circ}C/85%RH$ and then electrical and structural properties were analyzed by 4-point probe method, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Results: Sheet resistance of the top ITO layer increased with exposure time to the high temperature and humid atmosphere. Blunting of the protrusion morphology of ITO layer was observed for the degraded specimen, while no phase change was detected by XRD. Oxygen was detected at the edge area after 300 hours of exposure. Conclusion: Increase in electrical resistance of the degraded CIGS solar cell under high temperature and humid environment was attribute to the oxygen or water absorption.

• Environmental Analysis Health and Toxicology
• /
• 제11권1_2호
• /
• pp.19-29
• /
• 1996

Human exposure to volatile compounds in tap water can occur from inhalation and dermal absorption as well as direct ingestion. The relative contribution to total human exposure from these pathways has been considered to be important especially for VOC's (volatile organic compounds). In an attempt to reduce the uncertainty of the risk assessment, it has been suggested that the exposure assessment process could be significantly improved by adopting Monte-Carlo simulation. However, there is no actual data in Korea for each exposure parameter to determine the level of exposure, and the distributional pattern. Therefore, we surveyed water use patterns and behavior related to multi-route exposure to VOC's in household tap water in Korea, and compared these values to the those in western countries. In the first survey, we calculated daily water intake using data from a sample of 1322 persons of several cities in Korea. In the second survey, we obtained questionnaire data on exposure time for showering, bathing and household activities, and tap water intake from 851households in Korea. In the last survey, we measured the exposure parameters (exposure time, water use rate etc.) related to showers, baths, toilets, dish washing, washing and cooking, and tap water intake was surveyed. Also, the subjects were measured their body weight, height and tidal volume, etc. A diary, a flow meter and a measuring cup were used to measure these values as precisely as possible. Average daily water intake was ranged 0.79-1.71 L/day for adults in three surveys. Tap water intake measured by log-sheet during one week in third survey was 1.26 (average), 1.98 L/day (90 percentlie), respectively. These results were comparable with results from EPA (1.4, 2L/day). The average amount of water used by housewives in the third survey was 515.0 $\pm$ 564.6L/day. In usual activity, the amount of water used in the bathroom, the laundry and the kitchen was 140.0 $\pm$ 538.9, 148.0 $\pm$ 174.5, 229.3 $\pm$ 205.4 L/day, respectively. Exposure parameters such as water intake rate, exposure duration, body weight, inhalation rates in surveyed data of Korean people differed from those published from western countries. This could be attributed to variations in lifestyle, dietary habits and physiological characteristics.

• 한국대기환경학회:학술대회논문집
• /
• 한국대기환경학회 2006년도 춘계학술대회 논문집
• /
• pp.77-78
• /
• 2006

• Current Photovoltaic Research
• /
• 제6권3호
• /
• pp.81-85
• /
• 2018

The photovoltaic modules installed in the actual field are affected by various external environments and the electrical performance output value is generally lowered compared to initial output value. The most of photovoltaic modules consists of low iron glass, encapsulant (EVA), back sheet, frame and junction box assembly based on the solar cells. In this paper, the characteristics of encapsulant which is an important constituent material of photovoltaic module were verified by maximum power determination, electro luminescence images, yellowness index measurement, and gel content measurement after ultraviolet (UV) irradiation exposure. The most commonly installed 72 cells crystalline photovoltaic modules were tested after various UV exposure of 0, 15, 30, and $60kWh/m^2$ and compared with the reference module. After UV exposure of $15kWh/m^2$, which is the current international test condition, a small amount of change was observed in yellowness index and electroluminescence, while a gell content rapidly increased. At a cumulative dose of $60kWh/m^2$, which will be a new international test condition in the near future, however, the yellowness index increased sharply and showed the greatest output power drop.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 하계학술대회 논문집 B
• /
• pp.1147-1149
• /
• 1993

ZnO/$SnO_2$:F bilayer films have been prepared by pyrosol deposition method to develop optimum transparent electrode for use in amorphous silicon solar cells. The solution for $SnO_2:F$ film was composed of $SnCl_4{\cdot}5H_2O,\;NH_4F,\;CH_3OH$ and HCl, and ZnO films have been deposited on the $SnO_2:F$ films by using the solution of $ZnO(CH_3COO){_2}{\cdot}2H_2O,\;H_2O\;and\;CH_3OH$. These films have been investigated the variation of electrical and optical properties under the hydrogen plasma exposure. The sheet resistance of the $SnO_2:F$ film was sharply increased and its transmittance was decreased with the blackish effect after plasma treatment. However, the ZnO/$SnO_2:F$ bilayer film was shown hydrogen plasma durability because the electrical and optical properties was almost unchanged more then 60 seconds exposure time.

• 한국표면공학회지
• /
• 제55권3호
• /
• pp.173-179
• /
• 2022

This study presents a roll-to-roll process which is capable of Ag nanowire (AgNW) transfer from polyethylene terephthalate (PET) film to polycarbonate (PC) film. We developed a roll-to-roll machine that consists of two film suppliers, a coater of photo-curable resin, a film laminator, an ultraviolet (UV) exposure unit, and a film winder to facilitate large-area electrode transfer between different flexible substates. Using the process, optimal fabrication condition was investigated by parametric experiments in terms of the UV exposure time, number of thermal cycling, and exposure time of high temperature and humidity. A fabricated AgNW on PC film showed sheet resistance of 52 Ω/sq and optical transmittance of approximately 80 % over a range of visible light.

• Composites Research
• /
• 제31권1호
• /
• pp.17-22
• /
• 2018

장섬유 복합재료(Long Fiber Prepreg Sheet; LFPS)는 기존 연속섬유로 구성된 섬유 강화 복합재료에 비해 우수한 생산 효율과 성형성을 가지고 있다. 섬유 강화 복합재료가 타 재료와 혼성으로 사용이 되는 경우 이종 재료의 체결을 위해 접착 방법을 사용하게 되며, 접착부의 강도는 혼성 구조물의 강도를 결정하기 때문에 복합재료 접합부의 설계는 중요하다. 본 연구에서는 동시에 경화된 LFPS와 알루미늄의 접합부를 다양한 표면처리 조건과 온도 및 수분 환경조건에 따른 접착 특성을 평가하였다. 표면처리 기법으로는 기계적인 방법인 연마와 플라즈마 표면처리를 대상으로 하였다. 다양한 표면처리가 적용된 접착 조인트는 단면 겹치기 접착 조인트를 사용하여 실험하였다. 여러 조건들에서 접착 강도가 평가되었고 가장 적절한 조건이 도출되었다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
• /
• pp.127-130
• /
• 2011

The duplex waterproofing construction method has been investigated to improve various problems (how to fix the sheet, breaking, air/water pocket, and cracks caused by different materials) of the existing rooftop exposed waterproofing construction method. By using fiber sheet, Net PE fabric, and thixotropy urethane with high viscosity, the waterproofing construction method is to glue the ground and waterproof course by circular dot. The method is also to construct the waterproof course with high hardness by using waterproof membrane coatings in upper hybrid system. By gluing the ground and the waterproof course by circular dot, the study is expected to be useful to minimize the simultaneous breaking in the waterproof course as tensile stress is buffer in case of the ground crackling. Also, since the waterproofing construction method is good at moving and emitting vapor from the ground, it is considered to be effective to minimize any damages caused by air/water pocket and get loose of the waterproof course.

• 반도체디스플레이기술학회지
• /
• 제19권4호
• /
• pp.11-17
• /
• 2020

In this study, a new method for fabricating flexible transparent electrodes based on silver nanowire-polymer (AgNW-PEDOT:PSS) composite materials having a mesh pattern formed by a solution-based process without lithography was proposed. By optimizing conditions such as the amount of ultraviolet (UV) photosensitizer injected into the suspension of AgNW and PEDOT:PSS, UV exposure time, and deionized (DI) washing time, a clear and uniform mesh pattern was obtained. For the fabricated AgNW-PEDOT:PSS-based mesh-type electrodes, characteristics such as electrical sheet resistance, light transmittance, haze, and bending flexibility were analyzed according to the mixing ratio of AgNW and PEDOT:PSS included in the suspension. The fabricated mesh electrodes typically exhibited a low electrical sheet resistance of less than 20 Ω/sq while maintaining a high transmittance of 80% or more. In addition, it was confirmed from the results of analyzing the effect of PEDOT:PSS on the characteristics of the mesh-type AgNW-PEDOT electrode that the optical visibility was greatly enhanced by reducing the surface roughness and haze, and the bending flexibility was remarkably improved.