• 제목/요약/키워드: CENTER OF MASS

검색결과 4,911건 처리시간 0.035초

Mass constraints of coronal mass ejection plasmas observed in EUV and X-ray passbands

  • 이진이
    • 천문학회보
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    • 제36권1호
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    • pp.39.1-39.1
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    • 2011
  • Coronal mass ejection (CME) plasmas have been observed in EUV and X-ray passbands as well as in white light. Mass of CME has been determined using polarized brightness observed by the Large Angle and Spectrometric Coronagraph Experiment (LASCO) on board Solar and Heliospheric Observatory (SOHO). Therefore, this mass obtained from the LASCO observation indicates the total CME mass. However, the mass of CME plasma in different temperatures can be determined in EUV and X-ray passbands using observations by SOHO/EIT, STEREO/EUVI, and Hinode/XRT. Prominence/CME plasmas have been observed as absorption or emission features in EUV and X-ray passbands. The absorption features provide a lower limit to cold mass. In addition, the emission features provide an upper limit to the mass of plasmas in temperature ranges of EUV and X-ray. We determine the mass constraints using the emission measure obtained by assuming the prominence/CME structures. This work will address the mass constraints of hot and cold plasmas in CMEs, comparing to total CME mass.

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Electron-Impact Ionization Mass Spectroscopic Studies of Acetylene and Mixed Acetylene-Ammonia Clusters as a Structure Probe

  • Sung Seen Choi;Kwang Woo Jung;Kyung Hoon Jung
    • Bulletin of the Korean Chemical Society
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    • 제13권5호
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    • pp.482-486
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    • 1992
  • Ion-molecule reactions of acetylene and mixed acetylene-ammonia cluster ions are studied using an electron impact time-of-flight mass spectrometer. The present results clearly demonstrate that $(C_2H_2)_n^+$ cluster ion distribution represents a distinct magic number of n=3. The mass spectroscopic evidence for the enhanced structural stabilities of $[C_6H_4{\cdot}(NH_3)_m]^+$ (m=0-8) ions is also found along with the detection of mixed cluster $[(C_2H_2)_n{\cdot}(NH_3)_m]^+$ ions, which gives insight into the feasible structure of solvated ions. This is rationalized on the basis of the structural stability for acetylene clusters and the dissociation dynamics of the complex ion under the presence of solvent molecules.

이족보행 로봇의 무게중심 실시간 추정에 관한 연구 (On the Estimation of the Center of Mass of an Autonomous Bipedal Robot)

  • 권상주;오용환
    • 제어로봇시스템학회논문지
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    • 제14권9호
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    • pp.886-892
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    • 2008
  • In this paper, a closed-loop observer to extract the center of mass (CoM) of a bipedal robot is suggested. Comparing with the simple conversion method of just using joint angle measurements, it enables to get more reliable estimates by fusing both joint angle measurements and F/T sensor outputs at ankle joints. First, a nonlinear-type observer is constructed to estimate the flexible rotational motion of the biped in the extended Kalman filter framework. It adopts the flexible inverted pendulum model which is appropriate to address the flexible motion of bipeds, specifically in the single support phase. The predicted estimates of CoM in terms of the flexible motion observer are combined with measurements (that is, output of the CoM conversion equation with joint angles). Then, we have final CoM estimates depending on the weighting values which penalize the flexible motion model and the CoM conversion equation. Simulation results show the effectiveness of the proposed algorithm.

Application of Weibull Distribution Function to Analysis of Breakthrough Curves from Push Pull Tracer Test

  • Hyun-Tae, Hwang;Lee, Kang-Kun
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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    • pp.217-220
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    • 2003
  • In the case of the remediation studies, push pull test is a more time and cost effective mettled than multi-well tracer test. It also gives Just as much or more information than the traditionally used methods. But the data analysis for the hydraulic parameters, there have been some defections such as underestimation of dispersivity, requirement for effective porosity, and calculation of recovery of center of mass to estimate linear velocity. In this research, Weibull distribution function is proposed to estimate the center of mass of breakthrough curve for Push pull test. The hydraulic parameter estimation using Weibull function showed more exact values of center of mass than those of exponential regression for field test data.

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Determination of S- and R-Amlodipine in Rat Plasma using LC-MS/MS After Oral Administration of S-Amlodipine and Racemic Amlodipine

  • Yoo, Hye-Hyun;Kim, Tae-Kon;Lee, Bong-Yong;Kim, Dong-Hyun
    • Mass Spectrometry Letters
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    • 제2권4호
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    • pp.88-91
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    • 2011
  • The pharmacokinetic properties of S-amlodipine were studied using racemic amlodipine and single S-enantiomer (SK310) administration to rats. Plasma levels of the drug were determined using chiral liquid chromatography coupled with tandem mass spectrometry following solid phase extraction. The stereospecific analysis of amlodipine was performed on an ${\alpha}$-acid glycoprotein (AGP) column using a mobile phase comprising 10 mM ammonium acetate (pH 4.0) and propanol at a flow rate of 0.2 mL/min. This method was used to perform a comparative study of the pharmacokinetics of amlodipine and SK310. The results revealed that the pharmacokinetic profile of S-amlodipine after the administration of SK310 was comparable to that following the administration of the racemic mixture.

MMT Spectroscopy of Early-type Host Galaxies of Type Ia Supernovae

  • Kang, Yijung;Kim, Young-Lo;Lee, Young-Wook
    • 천문학회보
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    • 제42권1호
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    • pp.53.2-53.2
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    • 2017
  • The origin of the well-known correlation between Hubble residual of Type Ia Supernova (SN Ia) and mass of their host galaxies is yet to be fully understood. In our first paper of our YOnsei Evolutionary Supernovae Evolutionary Investigation (YONSEI) project, we found a significant (${\sim}3.9{\sigma}$) correlation between host galaxy mass (velocity dispersion) and population age from high S/N host spectra observed using LCO 2.5 m telescope. Since there is no correlation with metallicity, our result suggests that stellar population age is mainly responsible for the relation between host mass and HR. In order to explore this more directly, we have subsequently observed more sample of nearby early-type host galaxies using MMT 6.5 m telescope. In this poster presentation, we will report our progress in this project and show the preliminary results from our MMT observations.

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Urinary Metabolism and Excretion of Carbinoxamine after Oral Administration to Man

  • Jung, Byung-Hwa;Chung, Bong-Chul;Park, Jong-Sei
    • Biomolecules & Therapeutics
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    • 제4권3호
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    • pp.251-256
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    • 1996
  • The metabolism of carbinoxamine, 2-[(4-chlorophenyl)-2-pyridinyl-methoxy]-N, N-dimethylethaneamine, was studied in adult male volunteers after an oral dose of 15 mg. Solvent extracts of urine obtained with or without enzyme hydrolysis were analyzed by gas chromatography-mass spectrometry after derivatization with MSTFA/TMSCl (N-methyl-N-trimethylsilyltrifluoroacetamide/trimethyl chlorosilane). The structures of metabolites were determined based on the electron impact (EI) and chemical ionization (CI) mass spectra. Nonconjugated metabolites identified in the urine were carbinoxamine, nor-carbinoxamine, and bits-nor-carbinoxamine. Parent drug, nor-carbinoxamine, and bits-nor-carbinoxamine were also detected as conjugated forms. These metabolites observed in human urine were different from those previously reported in the rat. Urinary excretions of carbinoxamine were reached to maxima in 4 hours after drug administration with 4.9%-8.1% and 2.5-4.2% of the dose excreted during 24 h as carbinoxamine and its glucuronide, respectively.

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Al 전극에 의한 염료의 전기응집에서 물질전달 특성 (Mass transfer characteristics of continuous electrocoagulation for dyestuff solution using aluminum flat plate electrode)

  • Kim, Tak-Hyun;Park, Chulhwan;Shin, Eung-Bai;Kim, Sangyong
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2001년도 춘계학술대회 발표논문집
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    • pp.290-291
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    • 2001
  • The relationship between velocity, viscosity, diffusion coefficient, mass transfer coefficient and characteristic length and mass transfer data can be correlated by dimensionless relationship in electrolytic process. The performance of dyestuff removal was decreased as the flow rate of electrolyte was increased. It was due to the effect of retention time decreasing was superior to that of turbulent inlet mixing. Sh/Sc$\^$1/3/ vs Re plot for Al flat electrode did not showed the general tendency of the relationship between Sh/Sc$\^$1/3/ and Re. It can be thought that flow rate was not sufficiently high to increase the effect of mixing.

가속도계를 이용한 뇌졸중 환자의 보행 측정 (Walking Measures with a Tri-axial Accelerometer in Stroke Patients)

  • 오용섭;우영근
    • PNF and Movement
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    • 제11권2호
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    • pp.31-40
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    • 2013
  • Purpose : The purpose of this study was to measure the center of mass in body with stroke patients using a tri-axial accelerometer during walking. Methods : Twenty-eight patients were recruited and divided into two groups for this study. To measure their walking ability, Timed Up & Go (TUG) test and Fucntioanl Gait Assessment (FGA) were conducted and acceleration at rotation of center of mass (COM) in body were measure for each group. Results : In the comparisons between the two groups, the TUG and FGA were not significant differences and acceleration at rotation of COM was not significant differences also. Conclusion : Our research results suggesting that the accelerometer may be used as a testing tool and ongoing assessment tool for stroke patients during effects of intervention in walking.

Postnatal Management of Antenatally Diagnosed Patent Urachus with Bladder Prolapse

  • Choi, Hyun-Shin;Kim, Hae-Eun;Kim, Eun-Sun;Oh, Soo-Young;Chang, Yun-Sil;Seo, Jeong-Meen;Park, Won-Soon
    • Neonatal Medicine
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    • 제17권2호
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    • pp.262-264
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    • 2010
  • 요막관은 총 배설관에서 유래된 구조물로서, 태생기에 방광의 첨부와 제대 사이를 연결해주는 관이며, 임신 8-9개월에 완전히 막히게 되어 출생시에는 정중제인대로 남게된다. 드물게 요막관이 출생 후에도 요막관 게실, 요막관 낭종, 개방성 요막관 등으로 남아 있는 경우가 있는데, 그중 가장 심한 형태가 개방성 요막관으로 이를 통해 방광이 탈출되는 경우는 매우 드문 것으로 알려져 있다. 환아는 재태연령 41주, 출생체중 3,110 g, 아프가점수 1분 1점, 5분 7점, 정상 질식 분만되었으며, 산모는 35세로 임신 기간 중 약물 복용이나 다른 병력은 없었다. 재태연령 20주 2일에 시행한 산전 초음파상 낭성의 요막관 잔여물이 발견되었으며, 태아 자기공명영상에서 방광과 연결되는 낭종이 관찰되었다. 재태연령 40주 4일에는 고형종물 양상으로 관찰되어 초기의 낭종 형태에서 변화된 양상을 보였다. 출생 후 진찰 소견상, 제대 하방에 점막으로 둘러싸인 $3{\times}4cm$의 종물이 있었으며 요도로 삽입한 도관이 종물의 개구부를 통해 나오는 것이 확인되어 종물이 요도와 연결된 천공된 상태의 방광임을 추정할 수 있었다. 생후 1일에 시행한 복부 초음파상 수신증이나 다른 요로기형은 발견되지 않았으며, 생후 2일째 방광 복원술 및 요막관제거술을 시행하였다. 생후 9일째 시행한 배설성 방광 요로 조영술에서 방광 요로 역류는 없었고, 방광 기능은 좋은 것으로 확인되었다. 생후 10일째, 정상적인 배뇨를 보여 퇴원하였고 이후 특별한 문제없이 외래 추적 관찰 중이다. 저자들은 재태연령 20주 2일에 산전 초음파에서 요막관 잔여물로 추정되었던 낭종이 출생 후 요막관을 통한 방광 탈줄증으로 확진된 후 합병증 없이 수술적으로 완치되어 국내 최초로 보고하는 바이다.