• 제목/요약/키워드: Light Sensitivity

검색결과 614건 처리시간 0.032초

소형 GC 모듈의 개발 및 특성 (Development and Characteristic Study of a Portable Gas Chromatography)

  • 이명기;오준식;정광우
    • 대한화학회지
    • /
    • 제55권2호
    • /
    • pp.157-162
    • /
    • 2011
  • 대기 중 휘발성 유기화합물을 포함한 기체 성분을 현장에서 실시간으로 검출할 수 있는 소형 GC 모듈을 개발하였다. 상용의 모세관 또는 충진 컬럼을 열선과 함께 다발 형태로 감아 소형 케이스에 내장 하였고 소형 경량의 센서, 밸브, 펌프, 그리고 재충전이 가능한 운반기체 캐니스터 등을 사용하여 분석 시료의 채취, 주입, 및 분리 및 검출이 10 분 이내에 이루어지도록 하였다. 다양한 기체 혼합물을 소형 GC 모듈과 불꽃이온화 및 열전도도 검출기로 측정한 결과 모세관 컬럼의 경우 R=8.3의 분해능을 나타냈으며 우수한 감도는 물론 재현성 및 직진성을 나타내었다. 따라서 소형 GC 모듈은 대기 중 휘발성 유해물질의 농도 감시, 화학 공정 및 오염 배출원 규제 등에 매우 효과적으로 활용되리라 기대된다.

광 로직 게이트 구현을 위한 차동구조 Vertical Cavity Laser - Depleted Optical Thyristor에 관한 연구 (Differential switching operation of vertical cavity laser with depleted optical thyristor for optical logic gates)

  • 최운경;김두근;최영완
    • 대한전자공학회논문지SD
    • /
    • 제44권7호통권361호
    • /
    • pp.24-30
    • /
    • 2007
  • 본 연구에서는 광 논리 및 광 스위칭 시스템에 응용할 수 있는 수직 구조 레이저 - 완전 공핍 광 싸이리스터 (vertical cavity laser - depleted optical thyristor, VCL-DOT)를 제작하고, 본 연구실에서 제안한 차동 스위칭 방법을 이용하여 광 로직(AND, OR, NAND, NOR, INVERT) 함수를 구현하였고, 그 특성을 측정, 분석하였다. 제작한 VCL-DOT는 0.65 mA의 낮은 레이징 문턱 전류, 0.38 mW/mA의 높은 slope efficiency, 그리고 낮은 입력 광 파워에도 높은 민감도를 보인다. 차동 소자타입의 광 싸이리스터를 이용하면 복잡한 전기 회로를 이용하지 않고도, 집적화된 단일 소자에서 간단한 기준 광입력 시호의 파워를 제어함으로써 다양한 광 로직 게이트를 구현할 수 있다는 장점을 갖는다.

뉴로-퍼지 추론시스템을 이용한 입체 영상 카메라의 왜곡 영상 보정 (A Compensation for Distortion of Stereo-scopic Camera Image Using Neuro-Fuzzy Inference System)

  • 서한석;임화영
    • 한국전자통신학회논문지
    • /
    • 제5권3호
    • /
    • pp.262-268
    • /
    • 2010
  • 본 논문은 카메라의 고정 초점방식 렌즈를 통해 얻은 영상의 왜곡을 보상하여 왜곡된 이미지 좌표에서 본래의 좌표를 갖는 원영상으로 복원하는 연구이다. 이미지 센서의 다양한 영상 기기 발달과 활용으로 다방면의 산업분야에 확대 이용되고 있으나, 카메라의 소형화와 경량화 필요로 인해 렌즈의 굴곡에 의한 수신 영상의 왜곡이 영향을 미치는 경향이 많다. 특히, 입체 영상 카메라 응용 기기인 경우 좌, 우측 렌즈의 서로 다른 왜곡으로 입체감 저하 및 좌우 이미지 왜곡 등이 수반된다. 좌, 우측 카메라 수신 영상의 각 부분별로 본래의 좌표로 환산하는 근사식을 세우고 이들을 종합하는 방식으로 접근했다. 적응 뉴로-퍼지 추론시스템을 구성하여 소속 함수를 통해 분할하고 1차 Sugeno fuzzy 모델식으로 추정하여 좌, 우측 본래의 영상에 근접한 결과를 얻었다. 이로서 저가이며 소형 렌즈를 활용한 영상으로도 정확한 입체 영상 센싱 기능과 판별을 기대할 수 있게 된다.

Photo-Ames Assay를 이용한 광발암성 예측 (Prediction of Photo-Carcinogenicity from Photo-Ames Assay)

  • Hong Mi Young;Kim Ji Young;Chung Moon Koo;Lee Michael
    • 한국환경성돌연변이발암원학회지
    • /
    • 제25권1호
    • /
    • pp.6-12
    • /
    • 2005
  • Many compounds might become activated after absorption of UV light energy. In some cases, the resulting molecule may undergo further biological reaction of toxicological relevance related especially to the photo-carcinogenicity resulting from photo-genotoxicity. However, no regulatory requirements have been issued with the exception of guideline issued by the Scientific Committee of Cosmetology, Commission of the European Communities (SCC/EEC) on the testing of sunscreens for their photo-genotoxicity. Thus, the objectives of this study are to investigate the utility of photo-Ames assay for detecting photo-mutagens, and to evaluate its ability to predict rodent photo-carcinogenicity. Photo-Ames assay was performed on five test substances that demonstrated positive results in photo-carcinogenicity tests: 8-methoxypsoralen (photoactive substance that forms DNA adducts in the presence of ultraviolet A irradiation), chlorpromazine (an aliphatic phenothiazine an a-adr-energic blocking agent), lomefloxacin (an antibiotic in a class of drugs called fluoroquinolones), anthracene (a tricyclic aromatic hydrocarbon a basic substance for production of anthraquinone, dyes, pigments, insecticides, wood preservatives and coating materials) and retinoic acid (a retinoid compound closely related to vitamin A). Out of 5 test substances, 3 showed a positive outcome in photo-Ames assay. With this limited data set, an investigation into the predictive value of this photo-Ames test for determining the photo-carcinogenicity showed that photo-Ames assay has relatively low sensitivity (the ability of a test to predict carcinogenicity). Thus, to determine the use of in vitro genotoxicity tests for prediction of carcinogenicity,' several standard photo-genotoxicity assays should be compared for their suitability in detecting photo-genotoxic compounds.

  • PDF

환경교육과 경영교육의 접점, 환경경영교육의 현황과 과제 (Issues in the Current State of Environmental Management Education, the Nexus of Environmental Education and Management Education)

  • 윤순진;이주병;원길연;윤여창
    • 한국환경교육학회지:환경교육
    • /
    • 제25권1호
    • /
    • pp.25-34
    • /
    • 2012
  • Following the UN Conference on Environment and Development held in Rio de Janeiro, Brazil, in 1992, a number of companies began to incorporate the concept of Environmental Sustainability into their business activities. Soon after this, interest in business sustainability within the academic world began to grow and a number of universities in Europe and North America decided to develop environmental management education-related materials and curricula under the support from their respective govemments and private companies. Starting in 1996, a wide-range of environmental management education programs also began to appear in several Korean universities. However, in contrast with the gradual evolution of environmental management education into a single study field internationally, environmental management education in Korea has not become fully specialized, nor has it developed in a systematic manner. In order to enhance and facilitate domestic environmental management education in Korea, universities must put more effort into differentiating environmental management education courses from regular environmental courses through the development of curricula related to business management. The business world has an immense impact on the environment and international environmental regulations are steadily becoming stronger. In this light, environmental education programs need to extend their sphere of study not only to the spread of knowledge and sensitivity towards the environment among members of the general public, but also train businessmen to have an understanding of how their actions impact the environment.

  • PDF

Characterization and Photocatalytic effect of ZnO nanoparticles synthesized by spray-pyrolysis method

  • Lee, Sang-Duck;Nam, Sang-Hun;Kim, Myoung-Hwa;Lee, Kang-Suk;Kim, Young-Dok;Boo, Jin-Hyo
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2009년도 제38회 동계학술대회 초록집
    • /
    • pp.101-101
    • /
    • 2010
  • ZnO shows a direct band gap of 3.37eV, large exciton binding energy (~60 meV), high oxidation ability, high sensitivity to many gases, and low cost, and it has been used in various applications such as transparent electrodes, light emitting diodes (LEDs), gas sensors and photocatalysts. Among these applications ZnO as photocatalyst has considerably attracted attention over the past few years because of its high activities in removing organic contaminants generated from industrial activities. In this research, ZnO nanoparticles were synthesized by spray-pyrolysis method using the zinc acetate dihydrate as starting material at synthesis temperature of $900^{\circ}C$ with concentration varied from 0.01 to 1.0M. The physical and chemical properties of the synthesized ZnO nanoparticles were examined by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transformation Infrared (FT-IR), and UV-vis spectroscopy. The Miller indices of XRD patterns indicate that the synthesized ZnO nanoparticles showed a hexagonal wurtzite structure. With increased precursor concentration, a primary, secondary particle sizes of ZnO nanoparticles increased by 0.8 to $1.5{\mu}m$ and 15 to 35nm, and their crystallinity was improved. Methyleneblue (MB) solution ($1{\mu}M$) as a test comtaminant was prepared for evaluating the photocatalytic activities of ZnO nanoparticles synthesized in different precursor concentration. The results show that the photocatalytic efficiency of ZnO nanoparticles was gradually enhanced by increased precursor concentration.

  • PDF

A merging framework for improving field scale root-zone soil moisture measurement with Cosmic-ray neutron probe over Korean Peninsula

  • Nguyen, Hoang Hai;Choi, Minha
    • 한국수자원학회:학술대회논문집
    • /
    • 한국수자원학회 2019년도 학술발표회
    • /
    • pp.154-154
    • /
    • 2019
  • Characterization of reliable field-scale root-zone soil moisture (RZSM) variability contribute to effective hydro-meterological monitoring. Although a promising cosmic-ray neutron probe (CRNP) holds the pontential for field-scale RZSM measurement, it is often restricted at deeper depths due to the non-unique sensitivity of CRNP-measured fast neutron signal to other hydrogen pools. In this study, a merging framework relied on coupling cosmic-ray soil moisture with a representative additional RZSM, was introduced to scale shallower CRNP effective depth to represent root-zone layer. We tested our proposed framework over a densely vegetated region in South Korea covering a network of one CRNP and nine in-situ point measurements. In particular, cosmic-ray soil moisture and ancillary RZSM retrieved from the most time stable location were considered as input datasets; whereas the remaining point locations were used to generate a reference RZSM product. The errors between these two input datasets and the reference were forecasted by a linear autoregressive model. A linear combination of forecasts was then employed to compute a suitable weight for merging two input products from the predicted errors. The performance of merging framework was evaluated against reference RZSM in comparison to the two original products and a commonly used exponential filter technique. The results of this study showed that merging framework outperformed other products, demonstrating its robustness in improving field-scale RZSM. Moreover, a strong relationship between the quality of input data and the performance merging framework in light of CRNP effective depth variation has been also underlined via the merging framework.

  • PDF

피부 미백용 백미발효 한방 화장품에 대한 소비자 인식과 평가 (Consumer Perception and Evaluation of Cynanchi Atrati Radix Fermented Oriental Cosmetics for Skin Whitening)

  • 손창규;장은수;이삼근;방기정
    • 패션비즈니스
    • /
    • 제23권5호
    • /
    • pp.137-150
    • /
    • 2019
  • This study aimed to provide consumer perception and evaluation of natural Cynanchi Atrium Fermented Original Cosmetics for Skin Whitening that can improve skin by using oriental medicinal ingredients. The product was applied three times a day for two weeks by a total of 60 users who agreed to participate in a clinical trial assessing the usability and skin sensitivity to extracts that had already completed component safety testing. This study subjects reported which images were most reminiscent of Korea. They preferred products that bore Korean images because they felt trust and recognized that the quality of the cosmetics was excellent. The responses also showed that many consumers were willing to buy a product, even though it was luxurious, elegant, and expensive. The cognitive evaluation of Original Cosmetics was high and showed that the quality was likely to be good. The usability and CMF(Color, Material, Finishing) evaluation of Original Cosmetics showed good product the product is long-lasting and tightened and moisturized skin naturally. They are think about that this product it has moisturizing effects and good application for use, so it is light and soft to use. And had a whitening effect. It was intended to assist in the development of products that meet consumers' desires and expectations for safe, healthy, and beautiful skin by developing a skin whitening Original Cosmetics prototype that can inhibit the production of melanin and tyrosinase activity safely and effectively.

한의 복합 치료를 통해 시야결손에 개선을 보인 후대뇌동맥 폐색에 의한 뇌경색증 환자 1례에 대한 증례 보고 (A Case Report of a Homonymous Hemianopsia in a Stroke Patient Treated with Traditional Korean Medical Treatment)

  • 추홍민;김철현;이영웅;김광호;문연주;신혜령;안재윤;성강경;이상관
    • 대한한방내과학회지
    • /
    • 제40권5호
    • /
    • pp.797-803
    • /
    • 2019
  • Introduction: The aim of this study was to report the effect of Korean medicine treatments on a stroke patient with homonymous hemianopsia. Case Presentation: A 50-year-old male with a posterior cerebral artery infarction had continuously deteriorating symptoms of right homonymous hemianopsia, fatigue, dizziness, and light sensitivity. Treatment with Korean medicine therapy, including acupuncture and herbal medicine significantly improved the patient's symptoms. The result of a visual field test (VFI) was also improved after treatment, and no side effects were observed during treatment. Conclusion: Korean medicine treatment can be considered an effective treatment for homonymous hemianopsia in stroke patients.

김제 논에서 메탄 플럭스의 에디 공분산 관측 (Eddy Covariance Measurement of CH4 Flux in a Rice Paddy in Gimje, Korea)

  • ;윤주열;강남구;심교문;김준
    • 한국농림기상학회:학술대회논문집
    • /
    • 한국농림기상학회 2013년도 추계 학술발표논문집
    • /
    • pp.28-29
    • /
    • 2013
  • We have been measuring $CH_4$ flux in a rice paddy in Gimje using the eddy covariance method since July 2011. In order to measure the fast fluctuations of $CH_4$ concentration, an innovative LI-7700 open-path laser spectrometer is used. This high-precision, low power, light weight, low maintenance sensor enables us to operate it on a continuous and long-term basis. One particular feature, among other things, is the self-cleaning lower mirror which decreases maintenance requirements while ensuring more robust, continuous, high-quality dataset. Its cleaning is initiated at user-specified time intervals or a signal strength threshold, and its status is recorded as a diagnostic index. We have noticed that the operation of LI-7700 at Gimje site is quite challenging particularly due to its frequent mirror cleaning requirement and the associated sensitivity of the instrument. In this presentation, we present some field observation data regarding the mirror cleaning and their analysis, thereby suggesting the pertinent operation options for high-quality, maximum data retrieval in the field.

  • PDF