• 한국연초학회지
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• 제22권2호
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• pp.143-150
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• 2000

This study was carried out to investigate the effect of storage period on the physico-chemical properties of tobacco leaves expanded by $CO_2$. The flue-cured and burley tobacco leaves produced from 1996 to 1999 were processed, and stored for that year or 3 years in processing plant. As compared with 1996 crop, the expanded rate of flue-cured tobacco leaves in 1999 crop was higher approximately 18%, while that of burley was higher about 10%. The filling capacity of cigarettes was decreased as storage time became shorter, but the combustibility was improved. The rate of large particles (over 3.36mm) of expanded tobacco showed decreasing tendency as the storage period became longer. The change rate of chemical contents in tobacco leaves between before and after expansion had no significant difference among corp years. The tar and CO contents of cigarettes smoke were reduced in the case of flue-cured tobacco leaves as storage time became shorter, while they were slightly increased in the case of burley tobacco leaves. The ammonia content of burley leaves was decreased remarkably in 1996 and 1999 crop.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.125-134
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• 2004

The improvement of artificial respiration method has brought about the decrease in mortality of pulmonary diseases patients. Various respiratory curative methods, inclusive of HFOV (High Frequency Oscillatory Ventilation), have been developed for more effectual and less harmful management of acute respiratory failure. However, the mechanism of gas transfer and diffusion in a bronchiole has not yet been clarified in detail. As a first approach to the problem, we measured oscillatory flows in a Y-shaped micro-channels as bronchiole model by micro Particle Image Velocimetry(micro PIV). In order to establish the fundamental technique of PIV measurements on oscillatory air flow in a micro-channel, we used about 500-nm-diameter incense smoke particles, a diode laser, a high speed camera including an objective lens, and a HFOV, which is effective technique for medical care of pulmonary disease patients, especially, infants. The bronchiole model size is that parent tube is $500\{mu}m$ width and $500\{mu}m$ depth, and daughter tubes are $450\{mu}m$ width and $500\{mu}m$ depth. From this study made on the phenomenon of fluid in micro size bronchus branch of a lung, we succeeded to get time series velocity distribution in a micro scale bronchial mode. The experimental results of velocity distribution changing with time obtained by micro PIV can give fundamental knowledge on oscillatory airflow in micro-channel.

• 한국대기환경학회지
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• 제20권5호
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• pp.697-711
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• 2004

Severe haze, mist, and fog phenomena occurred in the central part of Korea during 15~25 May 2003 resulted in poor visibility and air quality. When these phenomena occurred, Korean peninsula was under the effects of anticyclone. The atmosphere was stable, and wind speed was so weak. Under this meteorological conditions, air quality was worse and worse. The characteristics of aerosol in Seoul, Incheon, and Gosan (Jeju) during this period are investigated from the $PM_{10}$. TSP concentrations and aerosol number concentrations. Concentrations of $PM_{10}$ and TSP measured at KMA increased upto 176 and 230 J.${\mu}g/m^3$ on 22 May 2003, respectively. Aerosol number concentrations of size range from 0.82 to 6.06 ${\mu}m$ increased in Seoul on 17, 19, and 21~24 May 2003, and the concentrations of $NO_2$ and $SO_2$had maximum value of 0.165 ppm at Gwanak Mt. and 0.036 ppm at Guro-dong on 23 May 2003, respectively. Result from analysis on heavy metal elements showed high concentrations of Zn, Pb, Cr, Ni, Cu, and Cd during 20~24 May 2003. This event is examined by comprehensive analyses of synoptic weather conditions, satellite images, concentrations of suspended particles and air pollutants, and heavy metal elements.

• 한국세라믹학회지
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• 제48권6호
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• pp.537-542
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• 2011

Magnesium hydroxide as a non-halogen flame retardant has increasing attention due to its non-toxicity, high decomposition temperature and smoke suppressant ability during combustion. For the application of magnesium hydroxide retardant to the textile by soaking and coating method, the prerequisite for the coating is a small particle size, stable dispersion, and adhesion to the textile. The dispersion of $Mg(OH)_2$ particles and stability of the coating was checked by monitoring the change of transmittance and backscattering by varying the types of dispersion agents, binder, solvent, and $Mg(OH)_2$ source, and their compositions in the coating. The $Mg(OH)_2$ dispersion coating was applied to PET(poly(ethylene terephthalate)) non-woven textile. The physical properties are characterized by surface morphology, amount of coating, particle dispersion, and adhesion test. The flame retardant $Mg(OH)_2$ coated textile has been compared by limited oxygen index(LOI) and thermal gravimetry and differential scanning calorimetry(TG-DSC). It was found that phosphorous additive may give synergistic effect on $Mg(OH)_2$ flame retardant coating to make the flame retardant PET non-woven textile.

• 한국안전학회지
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• 제27권3호
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• pp.57-62
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• 2012

The purpose of this paper is to find dangerous factors of a water purifier when water leaks due to inappropriate use and analyze the patterns of damaged parts in order to provide data for the examination of the cause of the problem. If the water purifier is inspected and managed by a non-specialist, when the FLC(Float Level Controller) at the top is inclined, water leakage may occur to the water purifier. The leaked water flows onto the cables and hoses and enters the thermostat terminal, heater, PCB, power supply connection connector, etc., becoming a dangerous factor that may cause a system failure, fire, etc. Due to the water that entered the input terminal, low noise and white smoke were generated at first. However, the flame gradually propagated due to the continuous inflow of moisture. It was found that when moisture reached the PCB, a carbonized conductive path was formed at the varistor terminal, input terminal, semiconductor device terminal, etc., and the flame became larger, which might result in a fire. From the metal microscope analysis of a damaged condenser terminal, it was found that the amorphous structure unique to copper cable disappeared, and voids, boundary surface and disorderly fine particles occurred. Also, in the case of the connector into which moisture penetrated, fusion and deformation occurred at the cable connection clips. The result of analysis of the power supply cable connector using a thermal image camera showed that most of the heat was generated from the cable connection clips and the temperature at the connection center was normal.

• 한국가스학회지
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• 제14권3호
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• pp.1-7
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• 2010

(주)시원기업에서 개발한 선회류식 세정전해기술을 이용한 실내공기오염물질 제거장치를 이용하여 다중이용시설에 관한 실내공기질 관리법에 따라 미세먼지, 냄새, VOC 등의 실내공기질을 기준치 이하로 제거하는 실험을 30분 동안 진행한 결과 미세분진(담배연기)은 $920{\mu}g/m^3{\rightarrow}112{\mu}g/m^3$로 저감되었고 가스상 물질은 포름알데히드(HCHO) 20ppm$\rightarrow$4ppm, 암모니아($NH_3$) 50ppm$\rightarrow$1ppm, 트리메틸아민($(CH_3CH_2)_3N$) 15ppm$\rightarrow$trace, 메틸에틸케톤($CH_3COC_2H_5$) 25ppm$\rightarrow$trace, 아세트알데히드($CH_3CHO$) 15ppm$\rightarrow$2ppm, 초산($CH_3COOH$) 20ppm$\rightarrow$trace, 아세톤($CH_3COCH_3$) 50ppm$\rightarrow$N.D로 고효율의 제거성능을 보여 선회류 세정장치에서 전해수를 세정하여 생성되는 세정필터를 이용한 실내공기질 저감기술로 실내환경을 쾌적하게 유지하는 것을 확인하였다. 오염물질을 제거하고 배출되는 다습한 공기는 실내습도를 40~60%정도로 유지하여 실내를 쾌적하게 하였다. 유해성제거실험으로 전기분해를 이용하여 대장균(E.coli)과 황색포도상구균(S.aureus)에 대해 살균시험을 수행한 결과 99.9%이상의 살균효과를 나타내었고 CODcr, 탁도는 완만한 저감곡선을 보여 세정수의 재이용 여부가 가능한 것을 확인하였다.

• 한국표면공학회지
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• 제12권3호
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• pp.207-216
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• 1979

Environmental pollution or contaminations caused by various kinds of pollutants have become one of most serious problems of our time. Environ mental pollution is the unfavoralble alteration of our surroundings, through direct or indirect effects of changes in energy patterns, rediation levels, chemical and physical constitution and abundances of organisms. These changes may affect humans directly or through their supplies of water and of agicultural and other biological products, their physical objects or possessions, or their opportunities for recreation and appreciation of nature. Pollutants that meet the criteria of this definition of environmental pollution are numerous: gases (such as sulfur dioxide and nitrogen oxides) and paniculate matter (such as smoke particles, lead aerosols, and asbestos) in the atmosphere; pesticides and radioactive isotopes in the atmosphee and in waterways; sewage, organic. chemicals, and phosphates in water; solid wastes on land; excessive heating (thermal pollution) of rivers and lakes; and many others. Some of these pollutants are introduced into the environment naturally, others by human actions, and most in both ways. Our major concer is with environmental pollution resulting wholly or largely as a by-product of human activities, because these can be controlled most readily. Environmental pollution cannot be solved by science and technology alone. It should be handled by an interdisciplinary approach with combined methods of science and technology as wen as social science disciplines for the better solution of this critical problem. In this respect, introducing "Environmental Science," a new scientific approach for the solution of environmental problems, which is now widely accepted by most developed countries of the world will be very helpful for systematization of theoretical basis for a new scientific approach to environmental pollution. Environmental science is "the study of all systems of air, land, water, energy, and life that surround Man. It includes all sciences directed to the system-level of understanding of the environment, drawing especially upon such disciplines as meteorology, geophysics, oceanography, and ecology, and utilizing to the fullest knowledge and techniques developed in such fields as physics, chemistry, biology, mathematics and engineering as well as many social science disciplines, such as economics, such as economics, law, political science and public administration." The components of this discipline are not new, for they are drawn from existing areas of science within biology chemistry, physics, and geoscience. What is really new about environmental science, however, is it siewpoint - its orientation to global problems, its conception of the earth as a set of interlocking, interacting systems, and its interest in Man as a part of these systems.

• Current Optics and Photonics
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• 제4권3호
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• pp.174-185
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• 2020

Multiscattering occurs when a laser transmits into dense atmosphere targets (e.g. fogs, smoke or clouds), which can cause depolarization effects even though the scattering particles are spherical. In addition, multiscattering effects have additional information about microphysical properties of scatterers. Thus, multiscattering can be utilized to study the microphysical properties of the liquid water cloud. In this paper, a Monte Carlo method was used to simulate multi-scattering transmission properties of Lidar signals in the cloud. The results showed the slope of the degree of linear polarization (SLDLP) can be used to invert the extinction coefficient, and then the cloud effective size (CES) and the liquid water content (LWC) may be easily obtained by using the extinction coefficient and saturation of the degree of linear polarization (SADLP). Based on calculation results, a microphysical properties inversion method for a liquid cloud was presented. An innovative multiscattering polarization Lidar (MSPL) system was constructed to measure the LWC and CES of the liquid cloud, and a new method based on the polarization splitting ratio of the Polarization Beam Splitter (PBS) was developed to calibrate the polarization channels of MSPL. By analyzing the typical observation data of MSPL observation in the northern suburbs of Nanjing, China, the LWC and CES of the liquid water cloud were obtained. Comparisons between the results from the MSPL, MODIS and the Microwave radar data showed that, the microphysical properties of liquid cloud could be retrieved by combining our MSPL and the inversion method.

• 대한환경공학회지
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• 제32권2호
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• pp.155-164
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• 2010

고기구이 스모크와 같은 바이오매스 소각에서 발생하는 스모크는 도시의 미세먼지중 유기성 탄소물질을 구성하는 주요 오염원이다. 미세먼지의 오염원 기여도를 산출하기 위한 화학수지모델(Chemical Mass Balance:CMB)에서는 배출원 오염물분포자료(Source Profile)가 필수이다. 바이오매스를 비롯한 고기구이 스모크의 오염물분포자료를 작성하기 위하여 유기성 지표물질들을 분석하였다. 고기구이에서 발생한 스모크를 PM10 채취기로 채취하여 용매추출, 유도체화반응, 중수소가 함유된 표준물질을 투입하여 Gas chromatography/Mass Spectrometry(GC/MS)로 팔미트산, 스테아르산, 올레인산과 같은 지방산과 콜레스테롤, 다환방향족탄화수소를 측정하였으며, 동시에 PM10 필터시료의 유기성(OC) 및 원소성 탄소(EC)를 OCEC 분석기에 의하여 측정하였다. 쇠고기구이 스모크로부터 채취한 PM10시료의 OC에서 콜레스테롤, 총포화지방산, 불포화지방산의 함량은 0.056 wt%, 2.727 wt%, 0.278 wt%이며, 돼지고기 구이 스모크로부터 채취한 PM10시료의 OC에서는 0.062 wt%, 2.022 wt%, 0.438 wt%를 차지하고 있었다. 쇠고기와 돼지고기 구이 스모크 OC에서 총 PAH화합물의 함량은 0.116 wt%와 0.044 wt% 이었는데, 그중에 단일 화합물로서 benzo(a)pyrene은 0.0071 wt%와 0.0023 wt%이었다. 콜레스테롤을 기준으로 각 지표물질의 무게 비율은 외국에서 발표된 고기구이 배출원 오염물분포자료와 거의 일치하여 유기성 에어로솔의 오염원 기여도를 산출하는 배출원 오염물분포자료로서 사용할 수 있음이 확인되었다.

• 재활복지
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• 제21권3호
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• pp.129-146
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• 2017

본 연구는 실내에서 화재 발생시 시각 장애인들을 지원하기 위한 영상 기반의 화재감지기를 제안한다. 건물 내에 화재가 발생하는 비상 상황 발생시 시각 장애인은 일반인보다 상황을 인지하는 것이 늦기 때문에 위험한 상황에 노출되기 쉽다. 기존의 연기 감지기와 같은 현재의 화재 감지 방법은 화재 발생시 발생하는 화학 센서 기반 기술을 사용함으로써 감지가 상대적으로 늦으며 화재가 확산된 후에 감지가 되는 등 낮은 신뢰성이 문제가 될 수 있다. 이를 보완하기 위해 영상 기반의 화재 감지 기술이 개발되었지만 낮은 정확도가 문제가 되어 실용화되지 못하였다. 최근 인공 지능을 위한 심층 학습 분야의 큰 발전으로 영상 내의 물체 인식률이 높아짐에 따라 관련 연구가 활발히 진행되고 있다. 따라서 본 연구에서는 보안 카메라 영상을 사용하여 화재를 감지할 수 있는 심층 학습 기반의 화재 감지기를 제안한다. 심층 학습 기반의 접근법은 영상에서 자동으로 특징을 학습할 수 있으므로 일반적으로 복잡한 상황에 대해서도 일반화가 가능하다. 본 논문에서는 화재감지 정확도와 속도 측면의 균형을 고려하여 두 개의 심층 합성곱 신경망 모델을 제안하였다. 실험을 통해 두 모델 모두 99%의 평균 정밀도로 화재를 감지할 수 있으며 첫 번째 모델은 초당 30장의 처리 속도와 76%의 정확도를 나타냈다. 두번째 모델은 초당 50장의 처리 속도와 61%의 정확도를 나타낸다. 또한 두 개의 모델의 메모리 사용량을 서로 비교하였으며 다양한 실제 화재 시나리오에서 테스트하여 신뢰할 수 있는 모델임을 증명하였다. 본 논문에 제안한 영상 기반 화재 감지기가 상용화된다면 상대적으로 실내 화재에 취약한 시각 장애인들의 안전에 도움이 될 것이다.