• 제목/요약/키워드: Current limiting

검색결과 746건 처리시간 0.027초

Sputum Inflammometry to Manage Chronic Obstructive Pulmonary Disease Exacerbations: Beyond Guidelines

  • Venegas, Carmen;Zhao, Nan;Ho, Terence;Nair, Parameswaran
    • Tuberculosis and Respiratory Diseases
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    • 제83권3호
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    • pp.175-184
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    • 2020
  • Quantitative sputum cytometry facilitates in assessing the nature of bronchitis associated with exacerbations of chronic obstructive pulmonary disease (COPD). This is not assessed in most clinical trials that evaluate the effectiveness of strategies to prevent or to treat exacerbations. While up to a quarter of exacerbations may be associated with raised eosinophil numbers, the vast majority of exacerbations are associated with neutrophilic bronchitis that may indicate airway infections. While eosinophilia may be a predictor of response to corticosteroids (oral and inhaled), the limited efficacy of anti-interleukin 5 therapies would suggest that eosinophils may not directly contribute to those exacerbations. However, they may contribute to airspace enlargement in patients with COPD through various mechanisms involving the interleukin 13 and matrix metalloprotease pathways. The absence of eosinophils may facilitate in limiting the unnecessary use of corticosteroids. The presence of neutrophiia could prompt an investigation for the specific pathogens in the airway. Additionally, sputum measurements may also provide insight into the mechanisms of susceptibility to airway infections. Iron within sputum macrophages, identified by hemosiderin staining (and by more direct quantification) may impair macrophage functions while the low levels of immunoglobulins in sputum may also contribute to airway infections. The assessment of sputum at the time of exacerbations thus would facilitate in customizing treatment and treat current exacerbations and reduce future risk of exacerbations.

고주파 공진현상을 이용한 CW CO2 레이저의 출력리플 최소화 (Minimization of a CW CO2 Laser Output Ripple by using High Frequency Resonance Phenomena)

  • 사쿠라;권민재;김희제;이동길;허국성
    • 전기학회논문지
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    • 제62권6호
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    • pp.798-802
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    • 2013
  • In a conventional DC power supply used for CO2 laser, the circuit elements such as a rectifier bridge, a current-limiting resistor, a high voltage switch, energy storage capacitors ans a high-voltage isolation transformer using high turn ratio are necessary. Consequently, those supplies are expensive and require a large space. Thus, laser resonator and power supply should be optimally designed. In this paper, we propose a new power supply using high frequency resonance phenomena for CW(Continuous wave) CO2 laser (maximum output of 23W with discharge length of 450mm). It consists of a transformer including leakage inductance, magnetizing inductance and half-bridge converter, a three-stage Cockcroft-Walton and PFC(Power factor correction) circuit. The output ripple voltage can be controlled the minimum of 0.24% under the high frequency switching of 231kHz. Furthermore, the output efficiency was improved to 16.4% and the laser output stability of about 5.6% was obtained in this laser system.

의약분업에 따른 약국 한약 활성화에 대한 조사 연구 (A Study for Activation of Pharmacy Oriental Medicine after the Separation of Prescribing and Dispensing Practice)

  • 최병철;김지인;손의동
    • 약학회지
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    • 제52권6호
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    • pp.471-479
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    • 2008
  • The purpose of this study is to investigate the best way that Oriental medicine contributes for activation of pharmacy management after the separation of prescribing and dispensing practice since July 2000. In order to investigate current pharmacy conditions for handling of Oriental medicine and many problems for administering the Oriental medicine to patients, a questionnaire was written with a list of questions related to pharmacy management with Oriental medicine, and given to 58 subjects via fax or personal visit during the period of April 21 to 30, 2003. The research results was as follows; In th 58 subjects, 45 subjects (77.6%) were pharmacists with a licence for dispensing Oriental medicine. 70.7% of subjects most likely preferred to extract granule as administering type of oriental medicine. About the motivation using Oriental medicine, the reason for activation of pharmacy management was 39.7%, second, the reason for resolving the limitation of treatment over western medicine was 25.9%. Oriental medicine for patients was mainly administered by recommendation with pharmacist (65.5%). In comparison with after and before the separation of prescribing and dispensing, 51.7% of subjects answered that sale volume was decreased after the separation. Concerning the ratio of total sales volume to Oriental medicine within 5 years, 50% of subjects expected that sales volume will increase positively. About treating Oriental medcine, 34.5% of subjects thought the problem is the regulation by limiting 100 kinds of formulary. The most important factor for increasing Oriental medicine selling amount was continueous education for various information of oriental medicine in case of 44.8% of sujects. The best pharmacy to handle oriental medicine was community pharmacy (36.2%). It was expressed the reason why many pharmacists have not been treated oriental medicine because lots of time needs for dispensing prescription from clinics in these 4 years after the separation of prescribing and dispensing. These results lead to the conclusion that the Oriental medicine at pharmacy will greatly increase within 5 years and will be very important portion for pharmacy management.

다문화가정 맞춤형 영양교육 프로그램과 운영시스템 개선을 위한 질적 연구 : 프로그램 제공자 측면 (Qualitative Study on Improvement of Operating System and Tailored Nutrition Education Program for Marriage Immigrants to Korea: Program Providers' Perspective)

  • 조미영;황지윤
    • 대한지역사회영양학회지
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    • 제22권4호
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    • pp.323-335
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    • 2017
  • Objectives: The purpose of this study is to analyze the current status of nutrition education programs for multicultural families and to provide policy suggestions for improvement. Methods: In-depth interviews of a total of 21 multicultural experts were conducted; 15 people were interviewed individually, while 6 people were interviewed in groups of three. Results: In-depth interviews revealed various problems related to the operation of nutrition education programs. The causes of problems were analyzed and categorized as four factors: systemic, practical, environmental and cultural. As for the systematic factors, insufficient linkage between related organizations and duplicate performance of several projects were identified as concerns Establishment of a control tower and strengthening the linkage among the related organizations may be needed to address this concern. With regard to practical factors, the study identified that language barriers, and lack of nutritional education media and tools translated into multicultural languages were limiting factors. These limitations the development of nutrition education materials that aretranslated into multiple languages, implementation of education programs that are different from the Korean education, and by providing interpreters. As for the environmental factors, low educational level and poor nutritional knowledge of multicultural women made it difficult for them to understand the contents of the education. Demonstration, practical training and urgent education on pregnancy and childbirth nutrition were identified as needs to address these concerns. Withregard to cultural factors, food culture conflict with Korean families, and difficulties in home practices were detected as concerns. Participants in the study suggested that getting education with family and facilitation of weekend and nighttime programs health of this community. Conclusions: Further studies are needed to adopt more effective and efficient nutrition intervention to promote the healthy eating of the married immigrant women based on the study results.

보현산천문대 1.8 m 망원경 제어시스템 현황 및 개선방안 (THE STATUS AND IMPROVEMENT PLAN OF 1.8 m TELESCOPE CONTROL SYSTEM AT BOAO)

  • 성현일;박윤호;이상민;이병철;성현철;오형일
    • 천문학논총
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    • 제27권3호
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    • pp.95-103
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    • 2012
  • We analyzed the current status of the telescope control system (TCS2) of the 1.8 m telescope in Bohyunsan Optical Astronomy Observatory (BOAO), and suggest a new TCS (TCS3) for the long term development of BOAO. The TCS2 was constructed in 1998 to replace the TCS1 which was installed with the telescope itself at the commencement of BOAO. One of the important parts of TCS is PMAC (Programmable Multi-Axis Controller), which is a general-purpose multi-axis motion controller. PMAC provides the direct interactive communication environment permitting users to command the controller directly with simple operations. This makes the setup, debugging, and diagnostics very easy. The TCS2 was operated stable for a long time, but the hardware and TCS computers have been deteriorated and are out of date now. The new TCS3 needs to be constructed based on a modern computer system. And functions such as pre-calculations of telescope limiting position, interworking with virtual observatory tools, and using GUI, etc should be added. Construction of the TCS3 will be a step creating a better observation environment for the Korean astronomical society.

바이러스 감속기의 가변 비율 제한기를 위한 자율적 주기 결정 (Autonomic Period Determination for Variable Rate Limiter of Virus Throttling)

  • 심재홍;손장완
    • 한국통신학회논문지
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    • 제32권1C호
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    • pp.67-77
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    • 2007
  • 바이러스 감속기(virus throttling)은 연결요청 패킷의 전송비율을 일정 비율 이하로 제한함으로써 웜을 탐지하는 대표적인 조기 웜 탐지 기술 중의 하나이다. 기존 바이러스 감속기 연구에서는 웜 탐지시간에는 크게 영향을 미치지 않으면서도 연결설정 지연시간을 단축시키기 위해 가중치 평균 지연 큐 길이를 적용하여 비율 제한기의 주기를 자율적으로 조절하였다. 기존 연구에서는 비율 제한기의 최소주기를 고정하고 또한 주기 값을 감소시키다가 다시 증가시키기 시작하는 반환점도 미리 고정하였다. 그러나 이러한 두 성능결정 요소는 웜 탐지시간과 연결 설정 지연에 서로 다른 영향을 미친다. 따라서 본 논문에서는 가변 비율 제한기의 최소주기와 반환점이 어떤 영향을 미치는지 실험을 통해 분석하고, 상황에 따라 이들 성능결정 요소들의 값을 결정할 수 있는 방안을 제시하고자 한다. 제안된 방법은 성능결정 요소를 고정시킨 기존 방법보다는 웜 탐지시간이나 연결설정 지연시간 단축에 더 효율적이라는 사실을 실험을 통해 확인하였다.

Improvement of Degradation Characteristics in a Large, Racetrack-shaped 2G HTS Coil for MW-class Rotating Machines

  • Park, Heui Joo;Kim, Yeong-chun;Moon, Heejong;Park, Minwon;Yu, Inkeun
    • Journal of Electrical Engineering and Technology
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    • 제13권3호
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    • pp.1166-1172
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    • 2018
  • Degradation due to delamination occurs frequently in the high temperature superconductors (HTS) coil of rotating machines made with 2nd generation (2G) HTS wire, and the authors have observed other similar cases. Since an HTS field coil for a rotating machine is required to have stable current control and maintain a steady state, co-winding techniques for insulation material and epoxy resin for shape retention and heat transfer improvement are applied during coil fabrication. However, the most important limiting factor of this technique is delamination, which is known to be caused by the difference in thermal expansion between the epoxy resin and 2G HTS wire. Therefore, in this study, the experimental results of mixing the ratio of epoxy resin and alumina ($Al_2O3$) filler were applied to the fabrication of small and large test coils to solve the problem of degradation. For the verification of this scheme, eight prototypes of single pancake coils with different shapes were fabricated. They showed good results. The energization and operation maintenance tests of the stacked coils were carried out under liquid neon conditions similar to the operation temperature of an MW-class rotating machine. In conclusion, it was confirmed that the alumina powder mixed with epoxy resin in an appropriate ratio is an effective solution of de-lamination problem of 2G HTS coil.

KODISA Academic Journal Strategy: Synopsis in 2016 and Vistas of the Future

  • Hwang, Hee-Joong;Youn, Myoung-Kil
    • 유통과학연구
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    • 제14권4호
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    • pp.5-11
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    • 2016
  • Purpose - The Education Ministry has plans to select top 10 percent academic journals among the domestic registration journals in NRF(National Research Foundation of Korea), and designate them as outstanding academic journals. To reflect this trend, KODISA has set its sights on paper publication rate and citation index with pushing forward globalism. First, this study will arrange the process of globalism and the current state of paper submission, and propose the direction of improvement in academic journals through understanding the characteristics of each major field. Research design, data, and methodology - KODISA has preceeded in examining and publishing research papers related to distribution field through indirectly or stimulating academic advancement. KODISA covers the whole fields in social science as well as in business administration and economics that associated with distribution field not limiting only within the range of distribution field. That is, the new subject that contributes to the progress in distribution field with original research can be a priority criteria in KODISA journal publication. Results - The major fields in papers published in KODISA can be categorized broadly as distribution field with economic and business administration point of view. Therefore, the distribution field with economic point of view includes the issues such as regulations, system, industry, market environment, distribution system, trade, and macroeconomics, etc. The business administration point of view in distribution includes distribution strategy, distribution organization, and distribution channel from the perspectives of the firm, etc. Conclusions - The aim of KODISA in 2020 is to be a global academic journal as SCI level of each journal in KODISA, JDS(Registration journal), IJIDB(Registration candidate), EAJBM(Registration candidate), JAFEB(Cabell's Registration journal). The KODISA journals have already settled as the largest academic society and journals of Korea in 2016 currently from humanities and social sciences area by the most gross in publication circulation, volumes, and types. Hereafter, KODISA will focus on the improvement for the objective indicators such as Impact Factor and Centrality index as qualitative growth as well as quantitative expansion. By doing so, KODISA will be a forum for developmental academic debate with attracting the world's greatest scholars' papers. Furthermore, they will be recognized journals and grow as the first-rate academic journals inside and outside of Korea.

Active Reaction Sites and Oxygen Reduction Kinetics on $La_1_{-x}Sr_xMnO_{3+\delta}$(x=0.1-0.4)/YSZ (Yttria-Stabilized Zirconia) Electrodes for Solid Oxide Fuel Cells

  • Lee, Hee Y.;Cho, Woo S.;오승모
    • Bulletin of the Korean Chemical Society
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    • 제19권6호
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    • pp.661-666
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    • 1998
  • Active reaction sites and electrochemical O2 reduction kinetics on La_{1-x}Sr_xMnO_{3+{\delta}} (x=0.1-0.4)/YSZ (yttria-stabilized zirconia) electrodes are investigated in the temperature range of 700-900 ℃ at $Po_2=10^{-3}$-0.21 atm. Results of the steady-state polarization measurements, which are formulated into the Butler-Volmer formalism to extract transfer coefficient values, lead us to conclude that the two-electron charge transfer step to atomically adsorbed oxygen is rate-limiting. The same conclusion is drawn from the $Po_2$-dependent ac impedance measurements, where the exponent m in the relationship of $I_o$ (exchange current density) ∝ $P_{o_{2}}^m$ is analyzed. Chemical analysis is performed on the quenched Mn perovskites to estimate their oxygen stoichiometry factors (δ) at the operating temperature (700-900 ℃). Here, the observed δ turns out to become smaller as both the Sr-doping contents (x) and the measured temperature increase. A comparison between the 8 values and cathodic activity of Mn perovskites reveals that the cathodic transfer coefficients $({\alpha}_c)$ for oxygen reduction reaction are inversely proportional to δ whereas the anodic ones $({\alpha}_a)$ show the opposite trend, reflecting that the surface oxygen vacancies on Mn perovskites actively participate in the $O_2$ reduction reaction. Among the samples of x= 0.1-0.4, the manganite with x=0.4 exhibits the smallest 8 value (even negative), and consistently this electrode shows the highest ${\alpha}_c$ and the best cathodic activity for the oxygen reduction reaction.

Normalized gestural overlap measures and spatial properties of lingual movements in Korean non-assimilating contexts

  • Son, Minjung
    • 말소리와 음성과학
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    • 제11권3호
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    • pp.31-38
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    • 2019
  • The current electromagnetic articulography study analyzes several articulatory measures and examines whether, and if so, how they are interconnected, with a focus on cluster types and an additional consideration of speech rates and morphosyntactic contexts. Using articulatory data on non-assimilating contexts from three Seoul-Korean speakers, we examine how speaker-dependent gestural overlap between C1 and C2 in a low vowel context (/a/-to-/a/) and their resulting intergestural coordination are realized. Examining three C1C2 sequences (/k(#)t/, /k(#)p/, and /p(#)t/), we found that three normalized gestural overlap measures (movement onset lag, constriction onset lag, and constriction plateau lag) were correlated with one another for all speakers. Limiting the scope of analysis to C1 velar stop (/k(#)t/ and /k(#)p/), the results are recapitulated as follows. First, for two speakers (K1 and K3), i) longer normalized constriction plateau lags (i.e., less gestural overlap) were observed in the pre-/t/ context, compared to the pre-/p/ (/k(#)t/>/k(#)p/), ii) the tongue dorsum at the constriction offset of C1 in the pre-/t/ contexts was more anterior, and iii) these two variables are correlated. Second, the three speakers consistently showed greater horizontal distance between the vertical tongue dorsum and the vertical tongue tip position in /k(#)t/ sequences when it was measured at the time of constriction onset of C2 (/k(#)t/>/k(#)p/): the tongue tip completed its constriction onset by extending further forward in the pre-/t/ contexts than the uncontrolled tongue tip articulator in the pre-/p/ contexts (/k(#)t/>/k(#)p/). Finally, most speakers demonstrated less variability in the horizontal distance of the lingual-lingual sequences, which were taken as the active articulators (/k(#)t/=/k(#)p/ for K1; /k(#)t/