• 제목/요약/키워드: absorption site

검색결과 297건 처리시간 0.03초

Electronic structure studies of CoFeRO (R=Hf,La,Nb) thin films by X-ray absorption spectroscopy

  • Song, J.H.;Gautam, S.;Chae, K.H.;Asokan, K.
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2009년도 제38회 동계학술대회 초록집
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    • pp.378-378
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    • 2010
  • We report the electronic structure of CoFeO-R (R=Hf, La, Nb) thin films studied by x-ray absorption spectroscopy (XAS). These ferrites thin films were prepared by pulsed laser deposition method and characterized by XAS measurements at O K-, Co and Fe L-edges. The O K-edge spectra suggest that there is a strong hybridization between O 2p and 3d electrons of transition metal cations and Fe $L_{3,2}$-edge spectra indicate that Fe-ions exist in $Fe^{2+}$ with tetrahedral site of the spinel structure. Divalent Co ions is also distributed in tetrahedral site with rare earth ions goes to octahedral sites of spinel structure. X-ray magnetic circular dichroism (XMCD) is also used to explain the symmetry and magnetic nature dependence on rare-earth ions.

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내외과계 환자의 정신과 약물치료에서 약물-약물 상호작용 - 고려대학교 부속병원의 자문조정의 경험을 통하여 - (Drug-drug Interactions between Psychotropic Agents and Other Drugs in Physically Ill Patients - Experience of Consultation-liason in Korea University Hospital -)

  • 이민수;이헌정
    • 생물정신의학
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    • 제6권1호
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    • pp.49-66
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    • 1999
  • Polypharmacotherapy, both psychotropic and nonpsychotropic, is widespread in various situations including psychiatric hospitals and general hospitals. As the clinical practice of using more than one drug at a time increase, the clinician is faced with ever-increasing number of potential drug interactions. Although many interactions have little clinical significances, some may interfere with treatment or even be life-threatening. The objective of this review is evaluation for drug-drug interactions often encountered in psychiatric consultation. Drug interactions can be grouped into two principal subdivisions : pharmacokinetic and pharmacodynamic. These subgroups serve to focus attention on possible sites of interaction as a drug moves from the site of administration and absorption to its site of action. Pharmacokinetic processes are those that include transport to and from the receptor site and consist of absorption, distribution on body tissue, plasma protein binding, metabolism, and excretion. Pharmacodynamic interactions occur at biologically active sites. In psychiatric consultation, these two subdivisions of drug interactions between psychotropic drugs and other drugs are likely to happen. We gathered informations of the drugs used in physically ill patients who are consulted to psychiatric department in Korea University Hospital. And we reviewed the related literatures about the drug-drug interactions between psychotropic drugs and other drugs.

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Skin depth profiling by using fiber optic probes in the near infrared

  • Woo, Young-Ah;jung, Suh-Eun;Kim, Hyo-Jin
    • 대한화장품학회:학술대회논문집
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    • 대한화장품학회 2003년도 IFSCC Conference Proceeding Book II
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    • pp.218-218
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    • 2003
  • Recently we showed the prototype portable device for the determination of human skin moisture by using near infrared spectroscopy. In order to optimize the acquiring condition of NIR spectrum of skin and control the target information of water depending the site such as epidermis and dermis, skin depth profiling was investigated changing the distance between illuminations and receiving of radiation in the terminal of fiber probe. The colleted light information could be controlled by changing the distance of the fiber optic probes. It was confirmed that the longer distance we used, the deeper site from the skin surface we could get information from in this study. Four kinds of probes with distances such as 0.03 mm, 0.1 mm, 0.5 mm, and 1.0 mm were used. In addition, the gap size from 0.3 mm to 3.0 mm was studied to control the intensity of water absorbance effectively and to avoid saturation of water absorption. We also investigated the reference materials depending the reflectance ratio for water absorption not to be saturated because of the strong absorptivity of water. Furthermore, spectroscopic information regarding free water and bound water around 1850 nm was investigated by using the different distance of fiber optic probes. This study would be great help to control the spectroscopic information of water to be measured depending the site where water exists.

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열원조건 분석 통한 흡수식 히트펌프 적용 열에너지 네트워크의 에너지 절감 예측 (A Study on the Energy Reduction of a Heating Network Through the Application of an Absorption Heat Pump)

  • 나선익;이영수;백영진;이길봉
    • 설비공학논문집
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    • 제29권5호
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    • pp.239-248
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    • 2017
  • At the $21^{st}$ Conference of the Parties (COP) of the United Nations Climate change Conference, representatives of the 195 member countries reached an agreement requiring all participating countries, including Korea, to establish proactive measures to fight climate change. Under this vision, energy network technologies are deemed as a key site of research towards meeting this goal. Herein, the headquarters of the Korea Institute of Energy Research (KIER) is a worthy site for carrying out energy network technology research insofar as it contains various heat sources. To prepare for this research, a study was conducted analyzing the heat sources at KIER based on measured data. The study also consisted of developeding simulation models to predict the amount of energy savings that could be derived by replacing an absorption chiller/heater with an absorption heat pump during winter seasons. In our simulation results, we observed a primary energy saving ratio of 65~72% based on the water temperature from the heat source of a coal power plant.

Current Methodologies for Membrane Permeability Assessment

  • Shin, Beom-Soo;Youn, Yu-Seok;Jeong, Seong-Hoon;Park, Eun-Seok;Lee, Mann-Hyung;Yoo, Sun-Dong
    • Journal of Pharmaceutical Investigation
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    • 제40권spc호
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    • pp.19-31
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    • 2010
  • Orally administrated drugs permeate the biological membrane by various transport mechanisms. The oral absorption potential is closely related to the physicochemical properties of the drug and interaction with the physiological factors surrounding the site of absorption. Assessment of the drug membrane permeability is an integral part of the early stage drug developmental process. Appropriate selection of the permeability screening method at the right stage of drug development process is important in achieving successful developmental outcomes. This review aims at introducing currently available in vitro and in vivo screening methods for the membrane permeability assessment.

가축분뇨수의 무단방류가 샛강오염에 미치는 영향 (Impact of Livestock-production Wastewater on Water Pollution)

  • 최홍림;손재호;류순호
    • 농촌계획
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    • 제2권1호
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    • pp.69-78
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    • 1996
  • Environmental impact assessment survey reflecting farmers` opinion on the residence and production space in rural settlement area by ORD showed that more than 86% of respondents thought their reservoirs and waterways (small rivers) were getting seriously contaminated primarily by garbage and livestock manure. A typical rural settlement unit was taken to assess the impact of improper management of livestock manure in the farms on the water quality of small river flowing down along the villages where swine and dairy farms were situated in Daejook 2, 3-ri, Seolseong-myun, Icheon-gun. Nitrogen compounds such as NO$_3$-N, NO$_2$-N, NH$_3$-N, and phosphorus compound H$_x$PO$_4$, DO, BOD$_5$, COD, and microbial density were analyzed to evaluate water quality at five test sites designated along the water stream. Tests showed. for example, BOD$_5$ at site 4 was average 9.2mg/l which was about 3~8 times higher than that of observation site 2 and 3, at which most livestock houses were situated. This is a clear evidence that the nutrients of livestock manure illegally discharged to small river can lead to an eutrophication of the river at downstream. A soil absorption system with aeration could be one of alternatives to treat the contaminated wastewater by livestock manure. The place at downstream, inbetween observation site 1 and 2, could be the best construction site for the treatment facility from the standpoint of the overall treatment efficiency, An enclosed composting system can also be regarded as a good alternative for treatment of the sludge which is the by-product of the soil absorption system operation.

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해수와 대기오염물질이 석조문화재에 미치는 영향: 감은사지 삼층석탑을 중심으로 (Effects of Seawater and Air Pollutants on Stone Cultural Properties: Three-Story Stone Pagodas in Gameunsa Temple Site)

  • 정종현;손병현;정민호;임헌호;김경원;김현규
    • 한국환경보건학회지
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    • 제33권4호
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    • pp.325-337
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    • 2007
  • The effect of seawater and air pollutants on the three-story stone pagodas on Gameunsa Temple Site have been studied in order to establish conservation basic plan. Also, an experimental study has been conducted to evaluate the effect of seawater salt and air pollutants on the weathering of granite. The results could be summarized as follows. Because the three-story stone pagodas on Gameunsa Temple Site are located outdoors, the external appearance has been largely deteriorated due to natural and artificial factors such as typhoon, wind, microorganisms, moisture, extreme change in temperature, air pollutants, and seawater, etc. When G.J fresh granite was dipped into the seawater, dissolution rate of three minerals (Mg, Ca, and K) are increased linearly until about 40 days and then increased abruptly. After seawater dipping experiments, the mineral compositions of the granite surface were lower then that of the G.J fresh granite but Poisson's ratio and absorption ratio were slightly increased. Therefore, from these results we can say that stone cultural properties could be weathered by seawater and air pollutants and it's considered being a meaningful experiment to study the conservation method of stone cultural properties from seawater.

Ba-Ferrite 단결정의 자기적 및 열적 현상에 관한 미시적 연구 (Microscopic Studies of the Magnetic and Thermal Properties in Ba-ferrite Single Crystal)

  • 서정철;최정완
    • 한국자기학회지
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    • 제19권4호
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    • pp.152-155
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    • 2009
  • Ba-ferrite 단결정을 제조하여 자기적 성질을 $M\"{o}ssbauer$ 분광법으로 연구하였다. 단결정 시료를 c-축 방향으로 얇게 절단하고 그 면에 감마선을 조사한 결과 Fe 이온의 스핀방향이 c-축과 일치하였고 시료 전체에 걸쳐 단일 결정체임을 확인하였다. 특히 감마선이 스핀과 나란한 경우 $M\"{o}ssbauer$ 흡수선 중에서 결정 내에 존재하는 Fe의 5개 자리 중에서 단지 4개 자리에서만 공명흡수선이 존재하였고 2b 자리에서는 전혀 공명흡수가 일어나지 않았다. 2b 자리에서의 공명흡수가 일어나지 않는 이유는 대칭성이 있는 2개의 우물 형 위치에너지의 중심 사이를 Fe 이온이 매우 빠른 속도로 c-축을 따라 진동하는 것으로 설명할 수 있다.

지역별 에어로졸 화학성분 농도 및 광학특성 비교 (Comparison of the concentration characteristics and optical properties of aerosol chemical components in different regions)

  • 소윤영;송상근;최유나
    • 한국환경과학회지
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    • 제28권1호
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    • pp.107-123
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    • 2019
  • The aerosol chemical components in $PM_{2.5}$ in several regions (Seoul, Busan, Daejeon, and Jeju Island) were investigated with regard to their concentration characteristics and optical properties. The optical properties of the various aerosol components (e.g., water-soluble, insoluble, Black Carbon (BC), and sea-salt) were estimated using hourly and daily aerosol sampling data from the study area via a modeling approach. Overall, the water-soluble component was predominant over all other components in terms of concentration and impact on optical properties (except for the absorption coefficient of BC). The annual mean concentration and Aerosol Optical Ddepth (AOD) of the water-soluble component were highest in Seoul (at the Gwangjin site) ($26{\mu}g/m^3$ and 0.29 in 2013, respectively). Further, despite relatively moderate BC concentrations, the annual mean absorption coefficient of BC ($21.7Mm^{-1}$) was highest in Busan (at the Yeonsan site) in 2013, due to the strong light absorbing ability of BC. In addition, high AODs for the water-soluble component were observed most frequently in spring and/or winter at most of the study sites, while low values were noted in summer and/or early fall. The diurnal variation in the AOD of each component in Seoul (at the Gwangjin site) was slightly high in the morning and low in the afternoon during the study period; however, such distinctions were not apparent in Jeju Island (at the Aweol site), except for a slightly high AOD of the water-soluble component in the morning (08:00 LST). The monthly and diurnal differences in the AOD values for each component could be attributed to the differences in their mass concentrations and Relative Humidities (RH). In a sensitivity test, the AODs estimated under RH conditions of 80 and 90% were factors of 1.2 and 1.7 higher, respectively, than the values estimated using the observed RH.

이트라코나졸의 랫트 소장으로부터의 흡수 (Absorption of Itraconazole from Rat Small Intestine)

  • 김영화;이용석;박기배;이광표
    • Journal of Pharmaceutical Investigation
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    • 제21권4호
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    • pp.215-222
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    • 1991
  • The absorption characteristics of itraconazole, which is an antifungal agent, from intestinal segments in the anesthetized rat i1l situ were investigated in order to design an effective oral drug delivery system. The pH-solubility profile of itraconazole, the rate and extent of absorption of itraconazole, the optimal absorption site(s) of itraconazole and the absorption enhancing effect of sodium cholate on itraconazole were examined in the present study. In situ single-pass perfusion method and recirculating perfusion technique using duodenum(D), jejunum(J) and ileum(I) were employed for the calculation of apparent permeability(Pe) and apparent first-order rate constant(Kobs). respectively. The results of this study were as follows; (1) Itraconazole showed appreciable aqueous solubility only at pH values of below 2.0. (2) pe(cm/sec) decreased in the following order: $D(10.24{\pm}1.78{\times}10^{-4})>J(8.86{\pm}0.79{\times}10^{-4})>I(3.78{\pm}0.13 X 10^{-4})$. (3) $Kobs(min^{-1})$ decreased in the following order: $J(17.12{\pm}3.19{\times}10^{-3})>D(13.37{\pm}0.6{\times}10^{-3})>I(11.05{\pm}0.91{\times}10^{-3})$. (4) The solubility of itraconazole markedly increased with the increase of the concentration of sodium cholate. (5) The addition of 10 mM sodium cholate significantly increased the apparent first-order rate constant of itraconazole in the ileum by a factor of 6.8.

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