• 제목/요약/키워드: Lead Dioxide

검색결과 101건 처리시간 0.025초

Development of Fast-Response Portable NDIR Analyzer Using Semiconductor Devices

  • Kim, Woo-Seok;Lee, Jong-Hwa;Park, Young-Moo;Yoo, Jai-Suk;Park, Kyoung-Seok
    • Journal of Mechanical Science and Technology
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    • 제17권12호
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    • pp.2099-2106
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    • 2003
  • In this paper, a novel fast response NDIR analyzer (FRNDIR), which uses an electrically pulsed semiconductor emitter and dual type PbSe detector for the PPM-level detection of carbon dioxide (CO$_2$) at a wavelength of 4.28 $\mu\textrm{m}$, is described. Modulation of conventional NDIR energy typically occurs at 1 to 20 Hz. To achieve real time high-speed measurement, the new analyzer employs a semiconductor light emitter that can be modulated by electrical chopping. Updated measurements are obtained every one millisecond. The detector has two independent lead selenide (PbSe) with IR band pass filters. Both the emitter accuracy and the detector sensitivity are increased by thermoelectric cooling of up to -20 degrees C in all semiconductor devices. Here we report the use of semiconductor devices to achieve improved performance such that these devices have potential application to CO$_2$ gas measurement and, in particular, the measurement of fast response CO$_2$ concentration at millisecond level.

유통 강황의 이산화황, 중금속 및 쿠르쿠민 함량 (Sulfur Dioxide, Heavy Metal and Curcumin Contents in Market-Available Turmeric (Curcuma longa L.))

  • 이영주;김애경;김욱희;이춘영;이현경;정선옥;이새람;김희선;김일영;유인실;정권
    • 한국약용작물학회지
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    • 제24권2호
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    • pp.121-128
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    • 2016
  • Background: Turmeric (Curcuma longa L.) that is used as a food material has antioxidant, anticancer and anti-inflammatory properties. Recently the demand for functional foods and drugs has increased. The present study was carried out to determined of contents of residual sulfur dioxide, heavy metals, ash, acid insoluble ash and curcuminoids in turmeric from the Seoul Yak-ryeong market. Methods and Results: A total of 31 samples were obtained. Residual sulfur dioxide was not detected in any samples. Heavy metals (arsenic, cadmium, lead and mercury) were analyzed by ICP-MS (Inductively Coupled Plasma Mass Spectrometer) and a mercury analyzer and were detected in the ranges of 0.00 - 0.28, 0.00 - 0.07, 0.00 - 0.29 and 0.002 - 0.027mg/g respectively. No significant difference were observed between the average heavy metal contents of domestic and imported tumeric. However, average content of ash in domestic samples (7.8%) were significantly higher than that in imported samples (6.1%), whereas that of curcuminoids was significantly higher in imported samples (47.6mg/g) than in domestic samples (11.2mg/g). The average content of acid insoluble ash was not significantly different between two sample types (0.9% in each). Conclusions: There are no specific standards for turmeric used as food materials. Therefore, this study can be provided as basic data for the establishment of quality standards for turmeric.

Heuristic based Energy-aware Resource Allocation by Dynamic Consolidation of Virtual Machines in Cloud Data Center

  • Sabbir Hasan, Md.;Huh, Eui-Nam
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제7권8호
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    • pp.1825-1842
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    • 2013
  • Rapid growth of the IT industry has led to significant energy consumption in the last decade. Data centers swallow an enormous amount of electrical energy and have high operating costs and carbon dioxide excretions. In response to this, the dynamic consolidation of virtual machines (VMs) allows for efficient resource management and reduces power consumption through the live migration of VMs in the hosts. Moreover, each client typically has a service level agreement (SLA), this leads to stipulations in dealing with energy-performance trade-offs, as aggressive consolidation may lead to performance degradation beyond the negotiation. In this paper we propose a heuristic based resource allocation of VM selection and a VM allocation approach that aims to minimize the total energy consumption and operating costs while meeting the client-level SLA. Our experiment results demonstrate significant enhancements in cloud providers' profit and energy savings while improving the SLA at a certain level.

가시광 응답형 광촉매 제조와 이를 활용한 실내공기환경 개선 적용 타당성 조사 (Feasibility Study of IAQ Enhancement by Visible Light Photocatalyst)

  • 이태규;윤우석;김동형;황철순;임지훈;윤정호;김영미
    • KIEAE Journal
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    • 제4권2호
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    • pp.37-40
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    • 2004
  • New visible photocatalyst(Nanovis$^{(R)}$) has been synthesized to overcome the barrier of limitation of UV light utilization of current $TiO_2$ photocatalyst. It was found that red shift of absorption spectrum to 550nm was achieved. Its physical properties were characterized by XRD, BET and TEM. It is also observed that Nanovis$^{(R)}$ has a photocatalytic activity for photodegradation of Trichloroethylene under visible light irradiation. V,VII group doped into substitutional sites of $TiO_2$ has proven to be indispensable for band-gap narrowing and photocatalytic activity. These test results lead us to conclude that Nanovis$^{(R)}$ can be used for IAQ improvemen and for photocatalytic water splitting to hydrogen.

전극함몰형 실리콘 태양전지의 제작시 스프레이 방법에 의한 타이타늄 옥사이드층의 적용에 관한 연구 (Titanium dioxide by spray deposition for buried contact silicon solar cells fabrication)

  • A.U. Ebong;S.H. Lee
    • 한국결정성장학회지
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    • 제6권2호
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    • pp.263-274
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    • 1996
  • 타이타늄 옥사이드층을 태양전지의 표면 보호막으로 사용시, 그 적합성에 대해 조사하였다. 스프레이법으로 형성된 타이타늄 옥사이드의 박막층은 태양전지 제조 과정중 사용되는 화학약품에 잘 견디며, 이 층을 사용함으로서 고온산화공정을 줄일 수 있다.

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고로슬래그 미분말 치환율에 따른 이산화탄소 양생 모르타르의 기초 물성 (Fundamental Characteristics of CO2-cured Mortar with Varied Rates of Blast Furnace Slag Fine Powder Substitution)

  • 류지수;장경수;나형원;형원길
    • 한국건축시공학회지
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    • 제24권1호
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    • pp.11-21
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    • 2024
  • 본 실험에서는 고로슬래그 미분말 치환율에 따른 이산화탄소 양생 모르타르의 기초 물성을 확인하였다. 실험 결과, 이산화탄소 양생은 CaCO3의 생성을 촉진하며 공극 감소와 조기 강도 발현에 영향을 준다. Ca(OH)2가 CaCO3보다 주된 강도 발현에 영향을 주며 고로슬래그 미분말 치환율이 높은 배합일수록 Ca(OH)2 생성이 감소한다. 하지만 Ca(OH)2가 소모된 이후에도 CaCO3를 통해 강도가 유지되며 이산화탄소 양생 이후 대기 중에 노출하여도 소요의 성능을 유지할 수 있을 것으로 전망된다. 고로슬래그 미분말 치환율이 50%를 초과할 경우 이산화탄소에 의한 성능 저하를 유발하므로 치환 비율을 조정할 필요가 있다.

이산화납 전극 제조 시 전기화학적 증착인자가 수산화라디칼 발생에 미치는 영향 (Effects of Electrodeposition Parameters on Electrochemical Hydroxyl Radical Evolution of PbO2 Electrode)

  • 심수진;윤제용
    • 대한환경공학회지
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    • 제38권12호
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    • pp.647-655
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    • 2016
  • Lead dioxide ($PbO_2$)는 전기화학적 고도산화공정(electrochemical advanced oxidation process, EAOP)에서 hydroxyl radical ($^{\bullet}OH$) 발생에 기반한 유기오염물 분해에 효과적인 전극물질이다. $PbO_2$ 전극의 대표적인 제조방법인 전기화학적 증착법(electrodeposition)의 주요 인자로는 전류/전압세기, 온도, 반응시간, Pb(II)의 농도, 전해질 종류 및 농도가 있다. 본 연구에서는 $Ti/PbO_2$ 산화전극을 전기화학적 증착법을 통해 전류인가 시간, 전류밀도, 온도, $HNO_3$ 전해질 농도를 각각 조절하여 제조하였고, $^{\bullet}OH$ 검출물질인 p-Nitrosodimethylaniline (RNO)의 전기화학적 탈색 측면에서 $^{\bullet}OH$ 발생에 대한 $PbO_2$ 증착인자의 영향을 조사하였다. 주요 결과로, $PbO_2$$^{\bullet}OH$ 발생 성능은 $PbO_2$ 증착과정에서 대체로 전류인가 시간이 길어질수록(1-90 min), 전류밀도가 감소할수록($0.5-50mA/cm^2$), 증착온도가 증가할수록($5-65^{\circ}C$), $HNO_3$ 전해질 농도(0.01-1.0 M)가 감소할수록 향상되었다. 특히, 0.01 M의 낮은 $HNO_3$ 농도 상에서 $20mA/cm^2$ 전류를 10분 이상 인가하여 증착시킨 $PbO_2$에서$^{\bullet}OH$ 발생이 가장 촉진되었다. RNO 탈색속도 측면에서 가장 성능이 좋은 $PbO_2$와 저조한 $PbO_2$ 사이에 최대 41% 정도 차이가 나타났다. $PbO_2$$^{\bullet}OH$ 발생 성능을 결정짓는 특성으로 $PbO_2$ 층 전도도, Ti 기판 산화, $PbO_2$ 결정크기를 고려한 결과, $PbO_2$ 층의 전도도 및 Ti 기판의 산화가 $^{\bullet}OH$ 발생에 주요하게 영향을 미치는 것으로 확인되었다. $PbO_2$ 층의 전도도 향상과 Ti 표면 산화 억제로 인한 $Ti/PbO_2$ 계면에서 전도도 향상이 $^{\bullet}OH$ 발생을 촉진시키는 효과를 가져왔다. 그리고 일부 전극에서는 표면에서 $PbO_2$ 결정 크기 증가가 $^{\bullet}OH$ 발생을 저감시키는 역할을 하였다.

자동차 선적작업장의 공기오염 실태조사 (Investigation into Air Pollution in Car Shipping Workshop in Pyeongtaek Port)

  • 김지호;원종욱;김치년;노재훈
    • 한국산업보건학회지
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    • 제16권1호
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    • pp.44-53
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    • 2006
  • This study purposed to investigate air pollution in car shipping yards and, for this purpose, we selected an outdoor open-air yard and an indoor ramp into the ship and measured the concentrations of sulfur dioxide, nitrogen dioxide, carbon monoxide, PM10, PM2.5 and heavy metals in the air. The results of this study are as follows. No significant difference was observed in temperature and humidity between the outdoor and indoor workshop, and the average air flow was 0.52 m/s in the indoor workshop, which is higher than 0.19 m/s in the outdoor workshop(p<0.01). The average concentrations of sulfur dioxide, nitrogen dioxide, carbon monoxide, PM10 and PM2.5 according to workplace were 0.03 ppm(${\pm}0.01$), 0.03 ppm(${\pm}0.01$), 0.46 ppm(${\pm}0.22$), $39.44{\mu}g/m^3$(${\pm}2.45$) and $5.45{\mu}g/m^3$(${\pm}1.15$) respectively in the outdoor workshop, and 0.15 ppm(${\pm}0.05$), 0.22 ppm(${\pm}0.06$), 8.85 ppm(${\pm}3.35$), $236.39{\mu}g/m^3$(${\pm}58.21$) and $152.43{\mu}g/m^3$(${\pm}35.42$) respectively in the indoor workshop. Thus, the concentrations of gaseous substances in the indoor workshop were 4.9-19.2 times higher than those in the outdoor workshop, and the concentrations of fine dusts were 5.9-27.9 times higher(p<0.01). In addition, according to the result of investigating pollutant concentrations according to displacement and the number of car loaded when shipping gasoline cars into the ship, no significant relation between the number of cars loaded and pollutants was observed in shipping passenger cars, but the concentrations of nitrogen dioxide and carbon monoxide got somewhat higher with the increase of the number of cars loaded(p<0.05). In addition, the concentrations of nitrogen dioxide, carbon monoxide, PM10 and PM2.5 in the air were significantly higher when shipping recreational vehicles, the displacement of which is larger than passenger cars, than when shipping passenger cars(p<0.01). On the other hand, the average heavy metal concentrations of the air in indoor workshop were: lead $-0.05{\mu}g/m^3$(${\pm}0.10$); chromium $-0.90{\mu}g/m^3$(${\pm}0.18$); zinc $-0.38{\mu}g/m^3$(${\pm}0.24$); copper $-0.18{\mu}g/m^3$(${\pm}0.22$); and manganese and cadmium not detected. In addition, the complaining rates of 'asthma,' a major symptom of chronic respiratory diseases, were 18.5% and 22.5% respectively in indoor workers and outdoor workers. Thus the rate was somewhat higher in indoor workers but the difference was not statistically significant. The complaining rates of 'chronic cough' and 'chronic phlegm' were very low and little different between indoor and outdoor workers. The results of this study show that the reason for the higher air pollution in indoor than in outdoor workshop is incomplete combustion of fuel due to sudden start and over-speed when cars are driven inside the ship. In order to prevent high air pollution, efficient management measures should be taken including the observance of the optimal speed, the improvement of old ships and the installation of efficient ventilation system.

공업단지 주변에서의 아황산가스 및 불화수소가 수도 생육에 미치는 영향 (Effect of Sulfur Dioxide and Hydrogen Fluoride on Rice Plant Growth in Industrial Estate)

  • 박완철;김광호;김기준
    • 한국작물학회지
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    • 제36권1호
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    • pp.17-21
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    • 1991
  • 다량의 대기오염물(SO2, HF)이 배출되고 있는 공업단지 주변에서 재배되고 있는 수도의 생육에 이들 대기오염물이 미치는 영향을 구명하기 위하여 수도의 각종 형질, 수량, 대기중의 오염물 농도, 엽내유황 및 불소함량과 엽피해율을 조사하여 시험한 결과는 다음과 같다. 1. 엽내유황함량과 대기중 아황산가스 농도간에는 높은 정의 상관이 인정되었다. 2. 엽피해율 조사치는 대기오염에 의한 수량감소의 가장 중요한 지표로 이용 할 수 있다. 3. 본 조사지역에서는 아황산가스보다 불화수소의 배출량이 적지만 엽피해의 발생에는 불소의 관련성이 아황산가스보다 높았다. 4 수량형질의 수량에 대한 기여정도는 주당수수가 제일 컸으며, 주당수수는 엽내 불소함량과 깊은 관련성이 인정되었다. 5. 엽내 유황함량은 수량 및 수량형질과 상관성이 인정되지 않았다.

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이산화티타늄을 이용한 대기정화 블록의 질소산화물 제거 성능 평가 (Performance Evaluation of Nitrogen Oxide Removal by Air Purification Blocks with Titanium Dioxide)

  • 오리온;김황희;박성기;차상선;박찬기
    • 한국농공학회논문집
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    • 제62권5호
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    • pp.39-46
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    • 2020
  • This study evaluated the nitrogen oxide (NOx) removal efficiency by air purification concrete blocks with titanium dioxide (TiO2). The concrete in the mixtures had a 30% water:cement ratio, to which TiO2 was added at 0%, 5%, and 10% of cement weight. The compressive strength reduction rate and removal efficiency of NOx were investigated. The result of the compressive strength test in the study indicated that addition rate of TiO2 did not lead to signifcant effect. In terms of the average removal efficiency of NOx, mix No. 1 using a TiO2 mixing ratio of 0% had a removal efficiency of 0.57% on average; thus, the removal effect w as not significant. For the other samples prepared by mixing, the average removal efficiencies for mix No. 2 (5% TiO2) were 58.86% and 62.05% for normal and washing surface treatments, respectively, and those of sample No. 3 (10% TiO2) were 59.94% and 67.61%. mixs No. 4 (5%) and No. 5 (10%), in which TiO2 diluted with distilled water was sprayed onto the block surface, had an average NOx removal efficiency of 61.72% and 68.48%, respectively. In terms of NOx removal efficiency, Mixs No. 3 and No. 5 with 10% TiO2 were better than Mixs No. 2 and No. 4 with 5% TiO2. In addition, analyzing the NOx removal efficiency results from the fixing method, it was capable to apply mixing (washing) and the diluted spray methods. Therefore, it was found that the diluted spray method applied in this study can be employed in any manufacture of air purification concrete blocks.