• Title/Summary/Keyword: PW

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A Design of Engine Exhaust Ejector for Smart UAV (스마트무인기의 엔진 배기이젝터 설계에 관한 연구)

  • Lee, Chang-Ho;Kim, Jai-Moo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.403-406
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    • 2006
  • An ejector is designed for the purpose of engine bay cooling. The primary flow of the ejector is the exhaust gas of the PW206C turboshaft engine. The mass flow of secondary flow is calculated by using the approximate analytic equation. For the purpose of verification of approximate analytic method, comparison is made with the results of Navier-Stokes turbulent flow solution. According to the results of CFD, the mixing of two flows is incomplete due to the short length of mixing duct.

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A PIV Measurement on Flow Characteristics inner Diffuser Pump Using High Resolution CCD Camera (고해상도 CCD 카메라를 이용한 디퓨져펌프 내부 유동특성에 대한 PIV 계측)

  • 김성윤;김범석;김정환;김유택;이영호
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2002.05a
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    • pp.161-166
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    • 2002
  • The resent experimental study is focused on the application of multi-point simultaneous measurement by PIV Particle Image Velocimetry) to guide vane region within diffuser pump. Various different kinds of rotational veto ity and changing clearance between Guide Vane and Impeller were selected as experimental condition. Optimized ross correlation identification to obtain velocity vectors is implemented with direct calculation of correlation coeffi cients. Fine optical setup concerned with PW performance is arranged for the accurate PW measurement of high peed complex flow. Variable flow pattern are represented quantitatively at the stator region.

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Developement of Efficient Algorithm to Eliminate Aliasing of Ultrasonic Pulsed Wave Doppler Signal (초음파 Pulsed Wave 도플러 신호의 Aliasing 제거를 위한 효율적인 알고리즘 개발)

  • Kim, G.D.;Hwang, J.S.;Ahn, Y.B.;Song, T.K.
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.213-214
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    • 1998
  • The important role of the ultrasonic Doppler system in the modem clinical medicine is to provide the clinical information of the vascular system. The ultrasonic pulsed wave(PW) Doppler system, a kind of the ultrasound Doppler system, is more available than the ultrasonic continuous wave(CW) Doppler system because it can evaluate the velocity and the direction of blood flow as well as the depth of vessel. However, the ultrasonic PW Doppler system has the disadvantage that the range of evaluating velocity of blood flow is limited(Nyquist limit). In order to solve this limit, we propose the algorithm for eliminating this aliasing in this paper. In addition, we propose the efficient signal processing algorithm.

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Adsorption Properties of Keggin-type Polyoxometalates on Carbon Based Electrode Surfaces and Their Electrocatalytic Activities

  • Choi, Su-Hee;Kim, Jong-Won
    • Bulletin of the Korean Chemical Society
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    • v.30 no.4
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    • pp.810-816
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    • 2009
  • The interactions between four Keggin-type POMs (${SiW_{12}O_{40}}^{4-},\;{PW_{12}O_{40}}^{3-},\;{SiMo_{12}O_{40}}^{4-},\;and\;{PMo_{12}O_{40}}^{3-}$) and glassy carbon (GC) and highly oriented pyrolytic graphite (HOPG) surfaces are investigated in a systematic way. Electrochemical results show that molibdate series POMs adsorb relatively stronger than tungstate POMs on GC and HOPG surfaces. Adsorption of POMs on HOPG electrode surfaces is relatively stronger than on GC surfaces. ${SiMo_{12}O_{40}}^{4-}$ species exhibits unique adsorption behaviors on HOPG surfaces. Surface-confined ${SiMo_{12}O_{40}}^{4-}$ species on HOPG surfaces exhibit unique adsorption behaviors and inhibit the electron transfer from the solution phase species. The catalytic activity of the surface-confined POMs for hydrogen peroxide electroreduction is also examined, where ${PW_{12}O_{40}}^{3-}$ species adsorbed on GC surfaces exhibits the highest catalytic efficiency among the investigated POM modified electrode systems.

Diurnal variation of atmospheric water vapor based on GPS observations over Taiwan

  • Cheng, Chihan;Liou, Yuei-An
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.1036-1038
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    • 2003
  • Diurnal variations in the atmospheric vapor at Banchiao of Taiwan are studied by analyzing 30 min-averaged data in the summer of 1998. The surface meteorological measurements were mainly obtained from the Central Weather Bureau (CWB) of Taiwan. It is found that precipitable water (PW) is increased in the afternoon. The maximum of precipitable water appears at around 0900 LST. The diurnal range of precipitable water is larger on the days with than without rainfall events. Rainfall events often occur in the afternoon and early morning. We also examine the difference in the characteristics of the PW signatures with and without rainfall according to the occurrence of the times for the rainfall peak and the onset of rainfall.

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Modal Fictionalism, Island Universe, and Multiverse (양상 허구주의, 고립된 우주(island universe), 그리고 다우주(multiverse))

  • Kim, Se-Hwa
    • Korean Journal of Logic
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    • v.6 no.1
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    • pp.33-50
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    • 2003
  • 본 논문에서 필자는 기존의 양상 허구주의의 번역 체계가 가지고 있는 세가지 난점을 극복할 수 있는 양상 허구주의의 새로운 번역 체계를 제시한다. 이 세 난점이란 (1) 많은 세계들의 존재를 받아들이지 않을 수 없게 된다. (2) 세계 간의 비교를 하게 하는 양상 진술문을 제대로 번역할 수 없다 (3) 어떤 양상 진술문에 내해 잘못된 진리치를 부여한다 이다. 이 세 난점을 극복하기 위한 필자의 제안은 세계-양화사의 범위 안에 등장하는 양화사들이 주어진 세계 내의 사물들만을 범위 내에 포함하는 루이스의 초기 번역 체계나 비한정적 양회사를 도입하는 루이스의 후기 번역 체계를 받아들이는 대신, 양화사를 조금씩 조금씩 비한정시키는 (unrestrict) 시키는 것이며, 필지 공식 번역 체계는 우주 (세계)의 부분전체론적 합으르 정의되는 "다우주(muitiverse)"라는 새로운 용어를 도입함으로써 얻어진다. 필자의 공식 번역 체계는 다음과 같다: P가 가능하다 iff PW에 의하면 P가 잠인 다우주가 존재한다 P가 필연적으로 참이다 iff PW에 의하면 모든 다우주에서 P가 참이다 마지막으로 필자는 비한정적인 세계 간의 비교를 하게 하는 양상 진술문을 적절하게 번역하기 위해서 필자의 번역 체계에 약간의 수정을 가한다.

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Transient Isomers of the Undecatungstomolybdo(V)phosphate and -silicate Anions

  • Cho, Yung-Whan;So, Hyun-Soo
    • Bulletin of the Korean Chemical Society
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    • v.5 no.2
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    • pp.65-68
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    • 1984
  • Reactions of $MoOCl_5^{2-}$ with $[PW_{11}O_{39}]^{7-}\;and\;[SiW_{11}O_{39}]^{8-}$ have been studied spectrophotometrically and several transient complexes have been discovered. Transient species initially formed are probably $[Mo_2O_4(PW_{11}O_{39})_2]^{12-}\;and\;[Mo_2O_4(SiW_{11}O_{39})_2]^{14-}$. Spectra change gradually, indicating formation of transient isomers of $[PMoW_{11}O_{40}]^{4-}\;and\;[SiMoW_{11}O_{40}]^{5-}$, which again transform into the stable isomers. The transient isomers absorb light much more strongly than the stable isomers in the visible range.

Definition of Security Requirement in Steps of Identification and Authentication (식별 및 인증 단계 보안 요건의 정의)

  • Shin, Seong-Yoon;Kim, Chang-Ho;Jang, Dai-Hyun;Lee, Hyun Chang;Rhee, Yang-Won
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.05a
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    • pp.175-176
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    • 2014
  • Identification and authentication of the security requirements of the application area. Individual ID for uniquely be identified. Standard length of the password is limited and should be applied in combination. And must be changed periodically. ID/PW authentication scheme non-reinforced must be provided. The authentication process is defined in the security requirements should be satisfied.

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Biomechanical Analysis of the Elderly Gait with a Walking Assistive Device (노인의 보행보조기구 사용 보행시 보행패턴의 변화연구)

  • Yoon, Suk-Hoon
    • Korean Journal of Applied Biomechanics
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    • v.17 no.2
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    • pp.1-9
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    • 2007
  • Walking is not only an essential component of the human mobility, but also is a good exercise. Inability to walk freely can reduce an individual's quality of life and independence substantially. Being a relatively low impact activity, walking is particularly good for the elderly and research has shown that regular walking in the elderly reduces the chance of fall-related injuries and mental diseases as well. In spite of the documented benefits of regular walking, it is still difficult to walk without the aid of assistive devices for the frail elderly who have lower extremity problems. Assistive walking devices(AWD), such as crutches, canes, hiking-poles, T-Poles and walkers, are often prescribed to the elderly to make their walking be safe and efficient. Many researchers have demonstrated the effects of AWDs such as reducing lower extremity loading, improved dynamic/gait stability, yet, no study has been done for gait pattern when the elderly gait with AWDs. Therefore, the purpose of this study was to examine whether T-Poles, one of the AWDs, change the elderly gait pattern. Eight community-dwelling female elderly participated in this study. Laboratory kinematics during walking with T-Poles(PW) and with out T-Poles(NPW) was assessed. PW showed significant increase in step width, stride length, gait velocity and decrease in swing time. No significances were found in lower body joint angles but meaningful trend and pattern were found. Maybe the reason was due to the participants. Our participants were healthy enough so that the effect of T-Poles was minimum. PW also showed typical gait phases which are no single support phase during a gait cycle. It indicates that walking with T-Poles may guarantee safe and confident walking to the frail elderly.

Persisting antibody reaction in paragonimiasis after praziquantel treatment is elicited mainly by egg antigens

  • Cho, Seung-Yull;Kong, Yoon;Yun, Doo-Hee;Kang, Shin-Yong;Kim, Lee-Soo;Chung, Young-Bae;Yang, Hyun-Jong
    • Parasites, Hosts and Diseases
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    • v.38 no.2
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    • pp.75-84
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    • 2000
  • Antibody responses in serum and cerebrospinal fluid (CSF) samples from patients with active and chronic paragonimiasis and in sera from patients on whom follow-up studies were done after praziquantel treatment were analyzed using antigens of Paragonimus westermani prepared from eggs, metacercariae, juveniles of 4-and 7-week old, adult worms and recombinant protein of 28 kDa cruzipain-like cysteine protease (rPw28CCP). The patient sera/CSFs of active and chronic paragonimiasis revealed strong antibody reactions against the crude extracts of 4-and 7-week old juveniles as well as against those from egg and adult. rPw28CCP also showed specific reaction to the sera with active paragonimiasis. After the treatment, levels of specific antibodies in the sera gradually decreased to negative range in most patients. In some cases with persisting high antibody levels, however, the reactions at 27 kDa egg Protein were sustained throughout the observation period of 34 months. The reactions at 35 and 32 kDa in adult extract and rPw28CCP disappeared rapidly after the treatment. Persistent antibody reactions even after successful treatment are provoked by continuous antigenic challenge from eggs which were not resolved by treatment.

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