• 제목/요약/키워드: Center of Mass

검색결과 4,862건 처리시간 0.034초

Histopathologic Diagnosis of Pleural Metastasis of Renal Cell Carcinoma Using Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration

  • Kang, Yeh-Rim;Jhun, Byung-Woo;Jeon, Kyeong-Man;Koh, Won-Jung;Suh, Gee-Young;Chung, Man-Pyo;Kim, Ho-Joong;Kwon, O-Jung;Han, Joung-Ho;Um, Sang-Won
    • Tuberculosis and Respiratory Diseases
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    • 제71권5호
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    • pp.355-358
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    • 2011
  • Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a useful, safe diagnostic modality for evaluating mediastinal and hilar lymphadenopathy. We report a 51-year-old male who presented with a left renal mass and multiple pleural masses without lung parenchymal lesions. The pleural masses were thought to be metastatic tumors or malignant mesothelioma. The patient underwent two percutaneous needle biopsies of the pleural mass, but the specimens were insufficient for a histopathological diagnosis. Because one pleural mass was adjacent to the right main bronchus, we decided to perform EBUS-TBNA for the pleural mass. As a result, sufficient core tissue was obtained with no complications, and the histopathological findings were consistent with metastatic papillary renal cell carcinoma. To our knowledge, this is the first case of using EBUS-TBNA for a pleural mass.

A Study on the Closed Linear Movement of the Center of Mass in the Rotatory Movement of a Rigid Body

  • Chung, Byung-Tae
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2002년도 ITC-CSCC -2
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    • pp.1216-1219
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    • 2002
  • It is understood so far that the center of mass does not make any linear movement from the rotatory movement of a rigid body in the closed system. However, it has been found that the center of mass of the system could make a closed linear movement due to production of an instantaneous center of mass by the Coriolis force in the rotatory movement of a rigid body in the closed system. The nature of the closed linear movement in the non-inertial system and that of the open movement in the inertial system are different from each other. That is, the closed movement is described like the time integration of frictional forces, which is different from the open movement usually considered and described like the time integration of external forces. It is shown in this paper that the Coriolis forces, called a fictitious force in the classical mechanics, is similar to the frictional force so that it causes to move the center of mass of a closed system. In this paper, following an explanation of the closed linear movement of a non-inertial system and the open movement of an inertial system, the source of the closed linear movement phenomenon of a rotatory rigid body is presented.

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Organic matrix-free imaging mass spectrometry

  • Kim, Eunjin;Kim, Jisu;Choi, Inseong;Lee, Jeongwook;Yeo, Woon-Seok
    • BMB Reports
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    • 제53권7호
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    • pp.349-356
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    • 2020
  • Mass spectrometry (MS) is an ideal tool for analyzing multiple types of (bio)molecular information simultaneously in complex biological systems. In addition, MS provides structural information on targets, and can easily discriminate between true analytes and background. Therefore, imaging mass spectrometry (IMS) enables not only visualization of tissues to give positional information on targets but also allows for molecular analysis of targets by affording the molecular weights. Matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS is particularly effective and is generally used for IMS. However, the requirement for an organic matrix raises several limitations that get in the way of accurate and reliable images and hampers imaging of small molecules such as drugs and their metabolites. To overcome these problems, various organic matrix-free LDI IMS systems have been developed, mostly utilizing nanostructured surfaces and inorganic nanoparticles as an alternative to the organic matrix. This minireview highlights and focuses on the progress in organic matrix-free LDI IMS and briefly discusses the use of other IMS techniques such as desorption electrospray ionization, laser ablation electrospray ionization, and secondary ion mass spectrometry.

Dynamics of an atomic wave packet in a standing wave quantized field

  • Tak, Jo-Yeong;Won, An-Gyeong
    • 한국광학회:학술대회논문집
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    • 한국광학회 2001년도 제12회 정기총회 및 01년도 동계학술발표회
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    • pp.252-253
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    • 2001
  • The purpose of this work is to investigate the dynamics of an atomic wave packet whose center-of-mass motion is quantized in a resonant standing wave cavity field. The mechanical aspect of the matter-field interaction has been extensively studied In the theme of atomic beam deflection, diffraction, or reflection by a standing-wave field. The effect caused in the behavior of spontaneous emission by the atomic center-of-mass motion, classical and quantized, in a standing wave cavity mode has been studied, and recently the one-atom laser with quantized atomic center-of-mass motion has been investigated. (omitted)

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An analytical model to decompose mass transfer and chemical process contributions to molecular iodine release from aqueous phase under severe accident conditions

  • Giedre Zablackaite;Hiroyuki Shiotsu;Kentaro Kido;Tomoyuki Sugiyama
    • Nuclear Engineering and Technology
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    • 제56권2호
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    • pp.536-545
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    • 2024
  • Radioactive iodine is a representative fission product to be quantified for the safety assessment of nuclear facilities. In integral severe accident analysis codes, the iodine behavior is usually described by a multi-physical model of iodine chemistry in aqueous phase under radiation field and mass transfer through gas-liquid interface. The focus of studies on iodine source term evaluations using the combination approach is usually put on the chemical aspect, but each contribution to the iodine amount released to the environment has not been decomposed so far. In this study, we attempted the decomposition by revising the two-film theory of molecular-iodine mass transfer. The model involves an effective overall mass transfer coefficient to consider the iodine chemistry. The decomposition was performed by regarding the coefficient as a product of two functions of pH and the overall mass transfer coefficient for molecular iodine. The procedure was applied to the EPICUR experiment and suppression chamber in BWR.

Simultaneous Determination of Synthetic Phosphodiesterase-5 Inhibitors in Dietary Supplements by Liquid Chromatography-High Resolution/Mass Spectrometry

  • Kim, So-Hee;Kim, Ho-Jun;Son, Jung-Hyun;Jeon, Byoung-Wook;Jeong, Eun-Sook;Cha, Eun-Ju;Lee, Jae-Ick
    • Mass Spectrometry Letters
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    • 제3권2호
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    • pp.50-53
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    • 2012
  • After success of sildenafil for the treatment of erectile dysfunction, a large number of its analogues have been approved from FDA. Recently, the illegal dietary supplements which include sildenafil, vardenafil, tadalafil, or analogues of these drugs as ingredient have been widely distributed. Therefore, the determination of the residue of synthetic phosphodiesterase- 5 (PDE-5) inhibitors in dietary supplements is highly required due to indiscriminate and unintentional overdose caused nausea, chest pains, fainting and irregular heartbeat. In this paper, we report a rapid and sensitive analytical method for the simultaneous determination of nine phosphodiesterase-5 inhibitors by liquid chromatography-high resolution mass spectrometry. The present method was found to be accurate and reproducible with 40 ${\mu}g$/g of the limit of quantification for the nine PDE-5 inhibitors. The developed method can be successfully applied to the analysis of the seven illegal dietary supplements.

롤러형 바퀴를 갖는 이동로봇 개발 (Development of Roller Wheel Mobile Robot)

  • 김순철;이수영;최재석
    • 로봇학회논문지
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    • 제9권4호
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    • pp.250-257
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    • 2014
  • In this paper, a new mobile robot, so called a rollerbot, is presented, which has single body and rugby-ball shaped roller wheel. A rollerbot has single point contact on ground and low energy consumption in motion because of the reduced friction. By changing center of mass using a balancing weight, a rollerbot is able to get steering force. The vertical position of mass center of the rollerbot in this paper is designed to lie inside radius of the roller wheel, so that to have stable equilibrium position. Thus, the posture and the steering control of the rollerbot can be easily done by changing the center of mass. Kinematics of the rollerbot is derived by transformation of differential motion in this paper.

자율운항선박의 안전운항을 위한 사고대응 지원서비스 설계 및 개발 (Design and development of accident response support service for safe operation of MASS)

  • 남경태;이영근;김남수;김천수
    • 한국항해항만학회:학술대회논문집
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    • 한국항해항만학회 2022년도 춘계학술대회
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    • pp.441-442
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    • 2022
  • 본 연구는 자율운항선박 운용에 따른 선박사고 발생 시 선박사고 단계 구분에 따른 사고대응 지원정보를 제공하는 자율운항선박 사고대응 지원서비스의 설계와 운영소프트웨어 개발에 대한 연구이다.

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ICP-MS에 의한 지하수 중의 Germanium 분석에 관한 연구 (Determination of Germanium in Spring Waters by Inductively Coupled Plasma Mass Spectrometry)

  • 박경수;송승연;심의섭;김선태
    • 분석과학
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    • 제11권2호
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    • pp.120-124
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    • 1998
  • 지하수 중의 극미량 germanium을 ICP-MS로 신속, 정확하게 분석할 수 있었으며 질량수 74를 분석하는 것이 가장 방해영향이 적음을 알 수 있었다. 지하수 중의 약 30%만이 $0.1{\mu}g/L$ 이상의 germanium을 함유하였고, 유기 germanium을 포함하는 지하수의 존재도 확인하였다.

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Construction of an Improved Tandem Time-of-flight Mass Spectrometer for Photodissociation of Ions Generated by Matrix-assisted Laser Desorption Ionization (MALDI)

  • Moon, Jeong-Hee;Yoon, So-Hee;Kim, Myung-Soo
    • Bulletin of the Korean Chemical Society
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    • 제26권5호
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    • pp.763-768
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    • 2005
  • An improved tandem time-of-flight (TOF) mass spectrometer for the photodissociation (PD) study of ions generated by matrix-assisted laser desorption ionization (MALDI), MALDI-TOF-PD-TOF, has been designed and constructed. Recording a full spectrum with better than unit mass resolution even in low mass range has been achieved without reflectron voltage stepping which was needed in the previous version. Other aspects of the improvement, such as those in the data system which now allow 10-100 times faster spectral acquisition than with the previous instrument, are described. Rationale for the ideas which have led to the improvements is presented also.