• 제목/요약/키워드: N-R Method

검색결과 1,650건 처리시간 0.031초

Physicochemical Characterization and Dissolution Properties of CS-891 with Different Crystallinity

  • Lee, Woo-Young;Park, Byoung-Woo;Park, Yong-Sun
    • Journal of Pharmaceutical Investigation
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    • 제35권4호
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    • pp.279-285
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    • 2005
  • Ground CS-891 (N-[1-(4-methoxyphenyl)-1-methylethyl]-3-oxo-4-aza-5a-androst-1-ene-$17{\beta}$-carboxamide) of poorly water soluble drug was obtained using a Heiko Seisakusho model TI-100 vibration mill, and samples with different crystallinity were prepared at mixture ratios of 10:0, 7:3, 5:5, 3:7 and 0:10 (intact;ground CS-891). Physicochemical characterizations were obtained using qualitative and quantitative X-ray diffractometry, different scanning calorimetry (DSC), scanning electron microscopy (SEM), Quantasorb surface area analyzer, and controlled atmosphere microbalance. With increase of amorphous CS-891 in mixture ratios, the intensities of X-ray diffraction peaks of crystalline CS-891 were decreased, whereas surface area, water absorption, and exothermic peaks in DSC were increased. The apparent solubility of ground CS-891 was $4.4\;{\mu}g/ml$ and the solubility of intact CS-891 was $3.1\;{\mu}g/ml$ at $37{\pm}1^{\circ}C$. The apparent precipitation rates of CS-891 in a supersaturated solution during the solubility test were increased with an increase of amorphous CS-891, and a crystalline form of CS-891 transformed from amorphous CS-891 after the solubility test was found by X-ray diffraction analysis, DSC and SEM. The dissolution profiles of CS-891 with different crystallinity at $37{\pm}1^{\circ}C$ by the USP paddle method were investigated, and the apparent dissolution rate constant of ground CS-891 was about 5.9-fold higher than that of intact CS-891. A linear relationships between the crystallinity of CS-891 and the apparent dissolution rate constant (r>0.96) were obtained.

Predicting the Frequency of Combustion Instability Using the Measured Reflection Coefficient through Acoustic Excitation

  • Bae, Jinhyun;Yoon, Jisu;Joo, Seongpil;Kim, Jeoungjin;Jeong, Chanyeong;Sohn, Chae Hoon;Borovik, Igor N.;Yoon, Youngbin
    • International Journal of Aeronautical and Space Sciences
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    • 제18권4호
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    • pp.797-806
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    • 2017
  • In this study, the reflection coefficient (RC) and the flame transfer function (FTF) were measured by applying acoustic excitation to a duct-type model combustor and were used to predict the frequency of the combustion instability (CI). The RC is a value that varies with the excitation frequency and the geometry of the combustor as well as other factors. Therefore, in this study, an experimentally measured RC was used to improve the accuracy of prediction in the cases of 25% and 75% hydrogen in a mixture of hydrogen and methane as a fuel. When the measured RCs were used, an unstable condition was correctly predicted, which had not been predicted when the RCs had been assumed to be a certain value. The reason why the CI occurred at a specific frequency was also examined by comparing the peak of the FTF with the resonance frequency, which was calculated using Helmholtz's resonator analysis and a resonance frequency equation. As the CI occurred owing to the interaction between the perturbation in the rate of heat release and that in the pressure, the CI was frequent when the peak of the FTF was close to the resonance frequency such that constructive interference could occur.

축소형 액체로켓엔진에서 기체산소/케로신 및 기체아산화질소/에탄올 연소 분무의 비교 (Comparison between GOx/Kerosene and GN2O/Ethanol Reactive Spray in a Subscale Liquid Rocket Engine)

  • 최송이;신봉철;이건웅;김도헌;구자예;박동근
    • 한국추진공학회지
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    • 제19권4호
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    • pp.61-68
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    • 2015
  • 초임계 연소에 대한 기초연구로써 축소형 액체 로켓 엔진에서 기체산소/케로신, 기체아산화질소/에탄올 추진제 조합의 정상상태 연소의 분무를 관찰하고 비교하였다. 분무의 가시화에는 shadowgraph 기법을 사용하였으며 실험결과를 분석하기 위해 shadowgraph를 후처리하여 밀도구배강도 이미지를 사용하였다. 정상상태 연소압력이 동일한 조건에서 기체산소/케로신 추진제의 액체 제트 표면의 굴곡이 심하고 분사기 팁 근처에서 급격한 밀도구배를 보이는 것이 관찰되었다. 밀도구배강도의 평균 이미지에서 분무 중심 길이를 도출하였으며 더 낮은 운동량 플럭스 비 조건에서도 기체산소/케로신의 분무중심 길이가 더 짧은 것으로 나타났다.

Localization of solar-hydrogen power plants in the province of Kerman, Iran

  • Mostafaeipour, Ali;Sedaghat, Ahmad;Qolipour, Mojtaba;Rezaei, Mostafa;Arabnia, Hamid R.;Saidi-Mehrabad, Mohammad;Shamshirband, Shahaboddin;Alavi, Omid
    • Advances in Energy Research
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    • 제5권2호
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    • pp.179-205
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    • 2017
  • This research presents an in-depth analysis of location planning of the solar-hydrogen power plants for electricity production in different cities situated in Kerman province of Iran. Ten cities were analyzed in order to select the most suitable location for the construction of a solar-hydrogen power plant utilizing photovoltaic panels. Data envelopment analysis (DEA) methodology was applied to prioritize cities for installing the solar-hydrogen power plant so that one candidate location was selected for each city. Different criteria including population, distance to main road, flood risk, wind speed, sunshine hours, air temperature, humidity, horizontal solar irradiation, dust, and land costare used for the analysis. From the analysis, it is found that among the candidates' cities, the site of Lalezar is ranked as the first priority for the solar-hydrogen system development. A measure of validity is obtained when results of the DEA method are compared with the results of the technique for ordering preference by similarity to ideal solution (TOPSIS). Applying TOPSIS model, it was found that city of Lalezar ranked first, and Rafsanjan gained last priority for installing the solar-hydrogen power plants. Cities of Baft, Sirjan, Kerman, Shahrbabak, Kahnouj, Shahdad, Bam, and Jiroft ranked second to ninth, respectively. The validity of the DEA model is compared with the results of TOPSIS and it is demonstrated that the two methods produced similar results. The solar-hydrogen power plant is considered for installation in the city of Lalezar. It is demonstrated that installation of the proposed solar-hydrogen system in Lalezar can lead to yearly yield of 129 ton-H2 which covers 4.3% of total annual energy demands of the city.

DEVCS 및 Discrete Time CAM을 이용한 심근 전도 시스템의 시뮬레이션 (The Simulation of Myocardium Conduction System using DEVCS and Discrete Time CAM)

  • 김광년;남기곤;손경식;이영우;전계록
    • 대한의용생체공학회:학술대회논문집
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    • 대한의용생체공학회 1997년도 춘계학술대회
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    • pp.150-155
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    • 1997
  • Modelling and Simulation of the activation process for the myocardium is meaningful to understand special excitation conduction system in the heart and to study cardiac functions. In this paper, we propose two dimensional cellular automata model for the activation process of the myocardium and simulated by means of discrete time and discrete event algorithm. In the model, cells are classified into anatomically similar characteristic parts of heart; SA node, internodal tracks, AV node, His bundle, bundle branch and four layers of the ventricular muscle, each of which has a set of cells with preassigned properties, that is, activation time, refractory duration and conduction time between neighbor cell. Each cell in this model has state variables to represent the state of the cell and has some simple state transition rules to change values of state variables executed by state transition function. Simulation results are as follows. First, simulation of the normal and abnormal activation process for the myocardium has been done with discrete time and discrete event formalism. Next, we show that the simulation results of discrete time and discrete event cell space model is the same. Finally, we compare the simulation time of discrete event myocardium model with discrete time myocardium models and show that the discrete event myocardium model spends much less simulation time than discrete time myocardium model and conclude the discrete event simulation method Is excellent in the simulation time aspect if the interval deviation of event time is large.

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북한의 간호교육 -반세기동안의 변화와 전망- (Nursing Education in North Korea: Past 50 Years and Future)

  • 이꽃메
    • 지역사회간호학회지
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    • 제12권2호
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    • pp.437-449
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    • 2001
  • Purpose: To understand the development of nursing education of North Korea after 1945. Method: First, collecting primary sources published in NK. Second, collecting secondary sources published in South Korea. Third, interview with South Korean medical personnels who visited NK. Forth, interview with medical personnels who escaped NK. Result: After 1945 NK increased health care facilities in short time and had the policy of training medical personnel in short time. Nursing education was focused on the basic practice. NK could begin free medical treatment for the laborer in 1947. Post Korean War restoration and free medical treatment system of national level in 1950s and 1960s served to the health promotion of NK population. The medical personnel training policy continued and the number of R.N. in NK had increased 13 times in 15 years. NK has tried to increase the quality of health care service and medical personnel since 1970s. Nursing education in medical colleges is three-year course but 6 month training courses in general hospitals continue. They focus on primary prevention and oriental medicine in nursing curriculum reflecting the characteristics of NK medial care. But English and high technology is very poor, and there is no computer related curriculum. Conclusion: nursing education in NK has developed reflecting the changes of NK society and health care since 1945. After 1980s NK is in deep economic depression and it is hard to recover from the state with their hands. In this state, we cannot expect the development of nursing education in NK.

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비휘발성 메모리 응용을 위한 VF2-TrFE 박막의 제작 및 특성 (Fabrications and Properties of VF2-TrFE Films for Nonvolatile Memory Application)

  • 정상현;변정현;김현준;김지훈;김광호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.388-388
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    • 2010
  • In this study, Ferroelectric vinylidene fluoride-trifluoroethylene (VF2-TrFE) copolymer films were directly deposited on degenerated Si (n+, $0.002\;{\Omega}{\cdot}cm$) using by spin coating method. A 1~5 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene (VF2:TrFE = 70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers at a spin rate of 2000 ~ 4000 rpm for 2 ~ 30 seconds. After annealing in a vacuum ambient at 100 ~ $200^{\circ}C$ for 60 min, upper aluminum electrodes were deposited by vacuum evaporation for electrical measurement. X-ray diffraction results showed that the VF2-TrFE films on Si substrates had $\beta$-phase of copolymer structures. The capacitance on highly doped Si wafer showed hysteresis behavior like a butterfly shape and this result indicates clearly that the copolymer films have ferroelectric properties. The typical measured remnant polarization ($P_r$) and coercive filed ($E_c$) values were about $5.7\;{\mu}C/cm^2$ and 710 kV/em, respectively, in an applied electric field of ${\pm}$ 1.5 MV/em. The gate leakage current densities measured at room temperature was less than $7{\times}10^{-7}\; A/cm^2$ under a field of 1 MV/cm.

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경쟁적 효소면역측정법을 이용한 환자 혈청 내 Thyroxine (T$_4$)의 검출 (Studies on the Rapid and Competitive Enzyme-linked Immunosorbent Assay for the Detection of Thyroxine (T$_4$) in Human Sera)

  • Sang-Wook Park;Jong-Bae Kim
    • 대한의생명과학회지
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    • 제5권1호
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    • pp.11-15
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    • 1999
  • 갑상선 질환의 진단에 필요한 갑상선 호르몬의 측정시 thyroxine (T$_4$)농도 측정방법이 가장 흔히 이용되고 있다. 과거에 많이 활용되어온 방사면역측정법 (RH)이 폐기물 처리 및 관리인원 등의 인적, 물적인 문제가 크게 대두되고 있는 점을 감안하면 효소결합면역측정법의 확립은 큰 의미가 있다고 하겠다. 본 연구에서는 thyroxine (T$_4$)에 대한 단클론 항체 (monoclonal antibody)를 이용하여 T$_4$에 horseradish-peroxidase를 화학적으로 결합시킨 microtiter plate에 HRP-conjugate T$_4$와 혈청내의 T$_4$간의 서로 경쟁적인 반응을 이용한 표준곡선을 얻었다. 그리고 이렇게 확립한 기법을 임상적인 갑상선질환 환자의 혈청을 기존의 chemiluminescence 방법을 이용하여 얻은 결과와 비교하여 본 실험에서 확립한 ELISA검사 수치의 유용성을 검토하였으며 이 방법의 임상이용 가능성을 검토하였다.

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Effect of Charge Carrier Lipid on Skin Penetration, Retention, and Hair Growth of Topically Applied Finasteride-Containing Liposomes

  • Lee, Sang-Im;Nagayya-Sriraman, Santhosh-Kumar;Shanmugam, Srinivasan;Baskaran, Rengarajan;Yong, Chul-Soon;Yoon, Sang-Kwon;Choi, Han-Gon;Yoo, Bong-Kyu
    • Biomolecules & Therapeutics
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    • 제19권2호
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    • pp.231-236
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    • 2011
  • The aim of this study was to investigate the effect of charge carrier lipid on the skin penetration, retention, and hair growth of topically applied finasteride-containing liposomes. Finasteride-containing liposomes were prepared by traditional thin film hydration method using Phospholipon$^{(R)}$ 85 G and cholesterol with or without charge carrier lipid (1,2 dimyristoyl-sn-glycero-3-phosphate or 1,2-dioleoyl-trimethylammonium-propane for anionic and cationic charge, respectively). Freshly prepared finasteride-containing liposome suspension was applied on the hairless mouse skin, and skin penetration and retention were measured using Keshary-Chien diffusion cell. Non-liposomal formulation (ethanol 10% solution containing 0.5 mg/ml of FNS) was also used as a control. The amount of finasteride in the diffusion cell and mouse skin was measured by HPLC. The hair growth was evaluated using depilated male C57BL/6N mice. Mean particle size of all finasteride-containing liposomes was less than a micron, and polydispersity index revealed size homogeneity. Skin penetration and retention studies showed that significantly less amount of finasteride was penetrated when applied as anionic liposome while more amount of the drug was retained. Specifically, in liposome prepared with 10% anionic charge carrier lipid, penetration was 12.99 ${\mu}g/cm^2$ while retention was 79.23 ${\mu}g/cm^2$ after 24 h of application. In hair growth study, finasteride-containing anionic liposomes showed moderate efficacy, but the efficacy was not found when applied as cationic liposomes. In conclusion, topical application of finasteride using anionic liposome formulation appears to be useful option for the treatment of androgenetic alopecia to avoid systemic side effects of the drug.

수질오염총량관리계획 수립을 위한 유달부하량 추정방법 연구 (A Study on Estimated Pollutant Delivery Load for the Basic Plan of TPLC)

  • 황하선;이한필;안기홍;박지형;김용석;이성준
    • 한국물환경학회지
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    • 제32권4호
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    • pp.375-383
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    • 2016
  • Total Pollution Load Control (TPLC) calculates and manages the allowable pollutant load that is discharged from the watershed, which can meet the water quality target. Delivery Ratio (DR) is generally used for predicting the variation of pollutant mass balance between the pollutants discharged from the watershed and a certain point in the stream, and it is very important for estimation of accurate allowable pollutant load. The concept of DR in TPLC is different from prevalent DR, because DR in TPLC includes both the discharge of pollutants from the watershed and the delivery mechanism. Therefore, DR in TPLC should be estimated by using a proper and unified methodology. The appropriate method and equation for estimation of DR in TPLC was developed through the review of various methodologies, and the applicability of the equation was evaluated in a study area (Geumho A). Determination coefficients (R2) of regression were shown to be relatively high (BOD 0.71~0.87, T-N 0.86~0.90, T-P 0.62~0.69). Applicability of the developed methodology and equations was evaluated as appropriate for TPLC, and it is suggested.