• 제목/요약/키워드: 전자수용체

검색결과 161건 처리시간 0.023초

ASP기반으로 한 기계산업체간의 성공적 전자상거래 구축을 위한 전략연구

  • Jeong, Sei-Hyun
    • 한국IT서비스학회:학술대회논문집
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    • 한국IT서비스학회 2002년도 창립기념 학술대회
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    • pp.77-95
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    • 2002
  • 오늘날 기업의 인터넷 활용상태를 보면 인터넷을 통한 기업내의 인트라넷(Intranet), 기업간의 엑스트라넷(Extranet)이 활발하게 구축되고 있으며, 전자상거래 시도를 촉진하는 매개체로서의 역할도 충실하게 수행하고 있는 실정이다. 인터넷 환경에서 전자상거래가 활성화를 이루면서 웹사이트의 시스템을 제대로 구축하고자 하는 노력이 시도되었으며, 그 적용범위 및 가능성이 증대되었다. 기업의 입장에서 보면, 인터넷상의 모든 기업이 경쟁자가 되므로, 생존을 위한 더욱 치밀한 기술 및 기법이 필요하다. 전 세계의 고객으로부터 정보사용 수준에 관한 요구가 쇄도할 수 있으며, 그 요구는 현재의 수준보다 훨씬 다양한 형태로 나타날 수 있다. 이러한 고객의 욕구를 만족시키기 위해서는 단순한 정보를 제시하는 것에서 벗어나 전문지식을 이용한 웹사이트 시스템을 개발하는 것이 필연적이다. 이 상황에 적절한 대책 사업인 경남지역 기계산업정보화사업을 중점으로 해서, 그 동안 추진해 온 사업을 앞으로의 전국 대상으로 한 관련된 기업체들을 보다 더 확대 수용할 수 있게 정부차원에서 전략적인 방안이 마련되어야 하겠다. 전자상거래를 성공적으로 적용하기 위한 전략적 방안은 국가차원에서 지역특성을 감안한 정보화 사업을 제대로 수행을 해야 한다. 이는 인프라 구축과 더불어 지속적인 사업이 되어야 한다. 대외적인 여세를 대비해 보면, 사업 추진해온 경남지역을 중심으로 한 경남지역의 4,877개 기계산업체를 대상으로 구성된 ASP(Application Service Provider) 기반 인프라를 현실화로 기하기 위해 국가차원에서 지속적으로 지원이 이루어진 여건 하에서 이용업체와 지원기관의 적극적인 협조체제가 이루어져야 만이 다가온 국제적 변화에 대응할 수가 있다는 것이다.

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Use of Nitrate and Ferric Ion as Electron Acceptors in Cathodes to Improve Current Generation in Single-cathode and Dual-cathode Microbial Fuel Cells (Single-cathode와 Dual-cathode로 구성된 미생물연료전지에서 전류발생 향상을 위한 전자수용체로서의 Nitrate와 Ferric ion의 이용)

  • Jang, Jae Kyung;Ryou, Young Sun;Kim, Jong Goo;Kang, Youn Koo;Lee, Eun Young
    • Microbiology and Biotechnology Letters
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    • 제40권4호
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    • pp.414-418
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    • 2012
  • The quantity of research on microbial fuel cells has been rapidly increasing. Microbial fuel cells are unique in their ability to utilize microorganisms and to generate electricity from sewage, pig excrement, and other wastewaters which include organic matter. This system can directly produce electrical energy without an inefficient energy conversion step. However, with MFCs maximum power production is limited by several factors such as activation losses, ohmic losses, and mass transfer losses in cathodes. Therefore, electron acceptors such as nitrate and ferric ion in the cathodes were utilized to improve the cathode reaction rate because the cathode reaction is very important for electricity production. When 100 mM nitrate as an electron acceptor was fed into cathodes, the current in single-cathode and dual-cathode MFCs was noted as $3.24{\pm}0.06$ mA and $4.41{\pm}0.08$ mA, respectively. These values were similar to when air-saturated water was fed into the cathodes. One hundred mM nitrate as an electron acceptor in the cathode compartments did not affect an increase in current generation. However, when ferric ion was used as an electron acceptor the current increased by $6.90{\pm}0.36$ mA and $6.67{\pm}0.33$ mA, in the single-cathode and dual-cathode microbial fuel cells, respectively. These values, in single-cathode and dual-cathode microbial fuel cells, represent an increase of 67.1% and 17.6%, respectively. Furthermore, when supplied with ferric ion without air, the current was higher than that of only air-saturated water. In this study, we attempted to reveal an inexpensive and readily available electron acceptor which can replace platinum in cathodes to improve current generation by increasing the cathode reaction rate.

Reduction of Hydraulic Conductivity in the Subsurface by the Formation of Aerobic Biobarrier (토양 내 호기성 생물벽체(Biobarrier)의 형성에 의한 투수계수의 제어)

  • Bae, Bum-Han;Oh, Je-Ill
    • Journal of Soil and Groundwater Environment
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    • 제12권2호
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    • pp.1-8
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    • 2007
  • A series of batch and column experiments were conducted for the development of biobarrier technology which can be applied to containment and reduction of contaminants in soil and ground waters. The growth kinetic constants of Pseudomonas fluorescens on glucose or molasses were determined using batch experiments. The maximum specific growth rate (Vmax) of P. fluorescens at $23^{\circ}C$ on glucose or molasses were $0.246\;hr^{-1}$ and $0.073\;hr^{-1}$, respectively. However, molasses was selected as carbon source due largely to the absence of lag phase of P. fluorescens growth on molasses and economic reason. In constant head column experiments, the hydraulic conductivity of the column soil reduced by $6.8{\times}10^{-3}$ times from $4.1{\times}10^{-2}cm/sec$ to $2.8{\times}10^{-4}cm/sec$ after the inoculation of P. fluorescens and administration of carbon source and nutrients. The biomass concentration was observed highest in the column inlet. Measurements of carbon source and electron accepter (dissolved oxygen) concentration showed that the growth of P. fluorescence, which is the main reason for hydraulic conductivity reduction, was limited not by the concentration of carbon source but by the concentration of electron acceptor.

Sulfate Reduction in the Marine Environments: Its Controlling Factors and Relative Significance in Mineralization of Organic Matter (해양환경의 황산염 환원율 조절요인 및 유기물 분해에 있어 황산염 환원의 중요성)

  • 현정호;이홍금;권개경
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • 제8권2호
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    • pp.210-224
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    • 2003
  • Sulfate reduction is a microbiological process which occurs ubiquitously in anaerobic marine environment. Sulfate reducing bacteria play a significant role in anaerobic decomposition of organic matter and regeneration of inorganic nutrients which supports the primary production in the water column (i.e., benthic-pelagic coupling) and, in special case, could be responsible for the harmful algal bloom in the coastal marine environment. Summary of the sulfate reduction rates reported in various marine sedimentary environments revealed that supply of organic substrates and presence of various electron acceptors (i.e., $O_2$, NO$_{3}$$^{[-10]}$ , Fe(III) and Mn(IV), etc.) for other aerobic and anaerobic respiration directly affect the sulfate reduction rate and relative significance of sulfate reduction in organic matter mineralization. Significance of temperature, macrophytes and bioturbation is discussed as factors controlling supply of organic substrates and distribution of electron acceptors. Finally, we suggest studies on the anaerobic microbiological processes associated with biogeochemical element cycles in the coastal environments of Korea where massive operation of organic enriched fish cage farm, frequent occurrence of toxic algal bloom and hypoxia and conservation of tidal flat are of major environmental issues.

Use of Plant Materials for Decontamination of Waste Water Polluted with 2,4-Dichlorophenol (2,4-Dichlorophenol로 오염된 폐수의 정화를 위한 식물체의 이용)

  • Lee, Jung-Eun;Park, Jong-Woo;Kim, Jang-Eok
    • Korean Journal of Environmental Agriculture
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    • 제18권3호
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    • pp.292-297
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    • 1999
  • This study was performed to estimate the possibility of use of plant materials as catalytic agents fur the decontamination of waste waters contaminated with organic pollutants by using 2,4-dichlorophenol(2,4-DCP) as a model pollutant. Plant materials containing high peroxidase activity were selected as catalysts for the removal of 2,4-DCP. Peroxidase activity, which plant materials were containing, was measured, and the greatest peroxidase activity was observed in shepherd's purse, followed by turnip, sweet potato, Chinese cabbage and white radish. The peroxidase activity in shepherd's purse was four times higher than that of horseradish purchased in U.S.A. Using shepherd' s purse and turnip, it was investigated the effect of various factors on the decontamination of 2,4-DCP through oxidative coupling. The removal of 2,4-DCP was extremely fast, and a maximal removal could be achieved within 3 min for shepherd' s purse and 15min for turnip. The pH range was from 3.0 to 8.0 and the amount of $H_2O_2$ added was 9mM when maximal removal was achieved(over 90%). No increasing removal of 2,4-DCP was observed due to increasing the amount of $H_2O_2$ added (over 9mM). The initial concentration affected the transformation of 2,4-DCP incubated with plant materials. When turnip was used as catalytic agent, it was observed decreasing transformation of 2,4-DCP due to increasing initial concentration.

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1,3-bisdicyanovinylindane 색소를 이용한 선택적 $Hg^{2+}$ 감지 특성

  • Kim, Su-Ho;Kim, Young-Sung;Kim, Sung-Hoon;Son, Young-A
    • Proceedings of the Korean Society of Dyers and Finishers Conference
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    • 한국염색가공학회 2009년도 제41차 학술발표회
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    • pp.19-20
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    • 2009
  • 최근 화학, 물리, 생명과학, 전기, 전자등의 다양한 분야에 활발하게 연구가 이루어지고 있는 초분자 화학은 선택적 분자인지를 위한 효율적인 골격구조와 나아가 다양한 계에 응용할 수 있다. 초분자 화학의 분자인지 과정의 특징은 일반적으로 수용체 (receptor 혹은 host)가 목표가 되는 기질 (substrate, analyte, 혹은 guest)에 대하여 선택적으로 식별하고 반응하는 것이다. 비공유 결합성 상호작용에 의하여 이루어지는 초분자 화학의 분자 인지 과정의 특징은 일반적으로 수용체 (receptor 혹은 host)가 목표가 되는 기질 (substrate, analyte, 혹은 guest)에 대하여 선택적으로 식별하고 반응하는 것이다. 이는 공유결합을 이용하는 분자화학과는 차별화 된 것이다. 수용체는 간단한 구조의 화합물 및 금속 이온들과 같은 기질과 가역적으로 상호 작용할 수 있는 착물을 형성한다. 최근들어 급격한 산업화가 진행되어 환경문제가 심각하게 대두 되어져 왔고, 그 중에서 특히 수은이나 카드뮴에 의한 질병, 납에 의한 중독 등 중금속에 의한 오염이 크게 나타남에도 불구하고, 현재 그러한 중금속을 검출함에 있어 많은 비용과 시간이 드는 문제점이 있다. 또한 우리에게 이로운 금속은 효율적 분석을 통해 환경계와 의료계에 많은 도움을 줄 것으로 사례되므로 화학센서 기술의 개발은 절실히 요구되어지고 있다. 이에 새로운 1,3-bisdicyanovinylindane 을 통해 $Hg^{2+}$ 금속의 감지 여부 알아보고, 그 특성을 파악하고자 한다. 1,3-indandion (2.18g, 14.9mmol), malononitrile (2.95g, 44.7mmol), ethanol 50ml를 20분간 상온에서 용해시킨다. 후에 sodium trihydrate acetate(3.05g)을 첨가한 후 5시간 동안 환류반응 시킨다. 이 과정에서 얻어진 용액을 필터과정을 통하여 에서 합성 반응 중에 생성된 불순물(1,3-dicyanovinylindane-1-one, monocondensation)을 제거한다. 필터과정을 통해 걸러진 미 반응 물질을 제�G 용반응욕액을 증류수(100ml)를 이용하여 희석시키고 난 후 염산을 이용, 산성화 시켜 고체 생성물을 얻어낸다. 이렇게 생성된 고체 생성물은 다시 필터 및 건조를 통하여 회색의 고체 화합물을 얻어낸다. 1,3-bisdicyanovinylindane과 금속이온에 대한 감응도를 확인하기 위하여 metanol/water(1:2)을 용매로 하여 금속이온의 농도를 변화시켜 발색특성을 살펴보았다. 본 색소화합물과 Hg2+에 대한 UV 흡광도 변화 적정결과와 그 화합물의 상태 살펴본 결과 금속이온이 0.2ml씩 더 참가되면서 색의 변화를 뚜렷하게 나타내었다. 반면 그 밖에 이온($Fe^{3+}$, $Ag^{2+}$, $Pd^{2+}$, $Zn^2$, $Fe^{2+}$, $Cu^{2+}$, $Pb^{2+}$)은 UV 흡광도 변화가 적거나 변화 자체가 없었다. 하지만 과량의 $Fe^{3+}$, $Ag^{2+}$, $Pd^{2+}$는 색상 변화를 나타내었으며,이와 같은 흡광도 변화는 금속에 따라 약간의 차이가 있지만, 420nm를 등흡수점으로 하여, 580nm의 파장 영역에 있는 흡수 밴드의 세기는 감소하는 반면 400nm 파장 영역에 있는 흡수 밴드의 세기가 증가하였다. 1,3-bisdicyanovinylindane 화합물은 다양한 생물계 및 환경계에서 요구되는 micro mol에서 milli mol 농도 영역의 $Hg^{2+}$ 이온의 선택적이고 민감한 검출과 정량적인 분석에 유용하게 사용될 수 있을 것이다.

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Preparation and Characterization of Deoxycholic Acid-Conjugated Low Molecular Weight Water-Soluble Chitosan Nanoparticles for Hydrophobic Antifungal Agent Carrier (소수성 항진균제 전달체로 응용하기 위한 데옥시콜릭산이 결합된 저분자량 수용성 키토산 나노입자의 제조와 특성)

  • Choi, Chang-Yong;Jung, Hyun;Nam, Joung-Pyo;Park, Yoon-Kyung;Jang, Mi-Kyeong;Nah, Jae-Woon
    • Polymer(Korea)
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    • 제33권4호
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    • pp.389-395
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    • 2009
  • To develop the carrier of hydrophobic antifungal agents based on low molecular weight water-soluble chitosan (LMWSC), LMWSC was chemically modified with deoxycholic acid (DA) which is one of the bile acid as a hydrophobic group. The nanoparticles (WSCDA) using DA conjugated LMWSC were characterized using dynamic light scattering (DLS) and transmittance electron microscope (TEM). The particle size of WSCDA ranged from 250 to 350 nm and increased with the number of DA substitution. The loaded itraconazole as an antifungal agent WSCDA nanoparticles (WSCDA-ITCN) were prepared by solvent evaporation method. The drug content and the loading efficiency were investigated approximately $9{\sim}10%$ and $61{\sim}68%$ by UV spectrophotometer, respectively. The release of drug from nanoparticles was slow and showed sustained release characteristics. Based on the results of release study that the higher DA contents in WSCDA, the slower the releasing rate, the WSCDA-ITCN could be used as an excellent antifungal agent.

Histological Changes of the Acupoint by Acupuncture Stimulation (침자(鍼刺)한 경혈(經穴) 부위(部位)의 조직학적 변화(組織學的 變化))

  • Kim, Jeong-Sang;Park, Min-Hee;Cho, Kwang-Phil;Jung, Hae-Man
    • Applied Microscopy
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    • 제30권1호
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    • pp.81-87
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    • 2000
  • This study has been carried out to understand histochemical and ultrastructural changes by acupuncture stimulation at the acupoint of the Zusanli (St. 36) in the rat. A lot of mast cells are observed in the peripheral of the hole with a sparrow-pecking and twistin -needle manipulation to the acupoint Zusanli for induction of 'Qi'. These cells contained a lot of granules with varied electron density and exocytosis granules were observed near the mast cell. H-bands of the muscle fiber that situated near the hole were shortened. It is assumed that these muscles are contracted by acupuncture stimulation. These results imply that functional relationship between mast cells in the dermis and Qi-sensation induced by acupuncture plays an important role on the specific receptor response to the mechanical stimulation.

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Isolation and Characterization of the Enterococcus sp. RKY1 for Biosynthesis of Succinic Acid. (숙신산 생합성을 위한 Enterococcus sp. RKY1의 분리와 특성)

  • 류화원;윤종선;강귀현
    • Microbiology and Biotechnology Letters
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    • 제26권6호
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    • pp.545-550
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    • 1998
  • Succinic acid, valuable $C_4$-dicarboxylic acid as a renewable alternative feedstock, is currently produced commercially by the petrochemical process, but extensive efforts have been devoted to establish the biological process for mass production of succinic acid. In this study, the bioconversion of fumaric acid to succinic acid was investigated. We isolated an Enterococcus sp. RKY1 KCTC 8890P, facultative bacterium, capable of the bioconversion of fumaric acid to soccinic acid very rapidly and efficiently. At batch fermentation, the amount of succinic acid production increased with increase in initial fumaric acid from 40 to 100 g/L. With fumaric acid of 70 g/L, the average specific and volumetric production rate, molar yield were reached up to 0.64 g/g.h, 4.87 g/g.h, and 96.5%, respectively. Maximum concentration of succinic acid of 88.9 g/L was achieved with molar yield of 89% with fumaric acid of 100 g/L in less than 20 hours.

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Example Development of Medical Equipment Applying Power Electronics Technique (전력전자 기술을 응용한 의료장비 개발 사례)

  • 고종선;이태훈;김영일;김규겸;박병림
    • The Transactions of the Korean Institute of Power Electronics
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    • 제7권6호
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    • pp.524-530
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    • 2002
  • A control of the body posture and movement is maintained by the vestibular system, vision, and proprioceptors. Afferent signals from those receptors are transmitted to the vestibular nuclear complex, and the efferent signals from the vestibular nuclear complex control the eye movement and skeletal muscle contract. The postural disturbance caused by loss of the vestibular function results in nausea, vomiting, vertigo and loss of craving for life. The purpose of this study is to develop a off-vertical rotatory system for evaluating the function of semicircular canals and otolith organs, selectively, and visual stimulation system for- stimulation with horizontal, vortical and 3D patterns. The Off-vortical axis rotator is composed of a comportable chair, a DC servo-motor with reducer and a tilting table controlled by PMSM. And a double feedback loop system containing a velocity feedback loop and a position feedback loop is applied to the servo controlled rotatory chair system. Horizontal, vertical, and 3D patterns of the visual stimulation for applying head mounted display are developed. And wireless portable systems for optokinetic stimulation and recording system of the eye movement is also constructed. The gain, phase, and symmetry is obtained from analysis of the eye movement induced by vestibular and visual stimulation. Detailed data were described.