• 제목/요약/키워드: Resonance Type

검색결과 1,085건 처리시간 0.03초

Facial diplegia as a delayed complication of scrub typhus

  • Baek, Jong Gyu;Hong, Hyo Lim;Park, Jae Han
    • Annals of Clinical Neurophysiology
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    • 제21권2호
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    • pp.98-101
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    • 2019
  • A 64-year-old man presented with facial diplegia occurring 2 weeks after scrub typhus diagnosis. The serum scrub typhus antibody titer was elevated to 1:5120. Brain magnetic resonance imaging revealed contrast-enhancement of the signal for both facial nerves. He was administered prednisolone. After two weeks, the symptoms improved, and after one month, he completely recovered from facial diplegia. This is the first case in the literature in which the patient exhibited facial diplegia, a delayed complication, in scrub typhus. Facial diplegia should be considered a type of cranial nerve palsy that may occur as a delayed complication of scrub typhus.

Analytical analysis for the forced vibration of CNT surrounding elastic medium including thermal effect using nonlocal Euler-Bernoulli theory

  • Bensattalah, Tayeb;Zidour, Mohamed;Daouadji, Tahar Hassaine
    • Advances in materials Research
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    • 제7권3호
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    • pp.163-174
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    • 2018
  • This article studies the free and forced vibrations of the carbon nanotubes CNTs embedded in an elastic medium including thermal and dynamic load effects based on nonlocal Euler-Bernoulli beam. A Winkler type elastic foundation is employed to model the interaction of carbon nanotube and the surrounding elastic medium. Influence of all parameters such as nonlocal small-scale effects, high temperature change, Winkler modulus parameter, vibration mode and aspect ratio of short carbon nanotubes on the vibration frequency are analyzed and discussed. The non-local Euler-Bernoulli beam model predicts lower resonance frequencies. The research work reveals the significance of the small-scale coefficient, the vibrational mode number, the elastic medium and the temperature change on the non-dimensional natural frequency.

Nonlinear dynamic responses of cracked atomic force microscopes

  • Alimoradzadeh, M.;Akbas, S.D.
    • Structural Engineering and Mechanics
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    • 제82권6호
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    • pp.747-756
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    • 2022
  • This study presents the nonlinear free and forced vibrations of a cracked atomic force microscopy (AFM) cantilever by using the modified couple stress. The cracked section of the AFM cantilever is considered and modeled as rotational spring. In the frame work of Euler-Bernoulli beam theory, Von-Karman type of geometric nonlinear equation and the modified couple stress theory, the nonlinear equation of motion for the cracked AFM is derived by Hamilton's principle and then discretized by using the Galerkin's method. The semi-inverse method is utilized for analysis nonlinear free oscillation of the system. Then the method of multiple scale is employed to investigate primary resonance of the system. Some numerical examples are presented to illustrate the effects of some parameters such as depth of the crack, length scale parameter, Tip-Mass, the magnitude and the location of the external excitation force on the nonlinear free and forced vibration behavior of the system.

A Comparative Study of the CNN Model for AD Diagnosis

  • Vyshnavi Ramineni;Goo-Rak Kwon
    • 스마트미디어저널
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    • 제12권7호
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    • pp.52-58
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    • 2023
  • Alzheimer's disease is one type of dementia, the symptoms can be treated by detecting the disease at its early stages. Recently, many computer-aided diagnosis using magnetic resonance image(MRI) have shown a good results in the classification of AD. Taken these MRI images and feed to Free surfer software to extra the features. In consideration, using T1-weighted images and classifying using the convolution neural network (CNN) model are proposed. In this paper, taking the subjects from ADNI of subcortical and cortical features of 190 subjects. Consider the study to reduce the complexity of the model by using the single layer in the Res-Net, VGG, and Alex Net. Multi-class classification is used to classify four different stages, CN, EMCI, LMCI, AD. The following experiment shows for respective classification Res-Net, VGG, and Alex Net with the best accuracy with VGG at 96%, Res-Net, GoogLeNet and Alex Net at 91%, 93% and 89% respectively.

HST용 유압폄프.모터의 압력맥동 저감 특성 (Pressure Ripple Reduction of Hydraulic Pump-Motor in HST)

    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 춘계학술대회 논문집
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    • pp.117-123
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    • 2003
  • This paper deals with pressure ripple and noise reduction characteristics for a hydrostatic transmission(HST) consisting of a variable axial piston pump connected in an open loop to a fixed displacement axial piston motor. Pressure ripples in HST is major source of vibration, which can lead to fatigue failure of components and cause noise. In order to reduce the pressure ripple, an annular tube type hydraulic filter proposes to absorb pressure ripples with the high frequencies components to achieve better noise attenuation in HST. The basic principle tube is applied to propagation of pressure wave, reflection, absorption in cross section of discontinuity and resonance in the hydraulic pipeline. It is experimently confirmed that a hydraulic filter is absorbed to be about 30∼40dB of pressure ripple with high frequencies. These results will assist in modeling and design of noise reduction in hydraulic control systems, and here, should provide a means of designing a quieter HST.

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Radiological assessment and follow-up of a nonsurgically treated odontoid process fracture after a motor vehicle accident in Egypt: a case report

  • Ahmad Mokhtar Abodahab
    • Journal of Trauma and Injury
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    • 제36권4호
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    • pp.411-415
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    • 2023
  • An odontoid process fracture is a serious type of cervical spine injury. This injury is categorized into three types based on the location of the fracture. Severe or even fatal neurological deficits can occur due to associated cord injury, which can result in complete quadriplegia. Computed tomography is the primary diagnostic tool, while magnetic resonance imaging is used to evaluate any associated cord injuries. These injuries can occur either directly from the injury or during transportation to the hospital if mishandled. There are two main treatment approaches: surgical fixation or external nonsurgical fixation, with various types and models of fixation devices available. In this case study, computed tomography follow-up confirmed that external fixation can yield successful results in terms of complete healing, even in cases complicated by other factors that may impede healing, such as pregnancy.

드문 형태의 자궁 경부 혈관근종: 특이한 자기공명영상 소견을 포함한 증례 보고 (A Rare Angioleiomyoma of the Uterine Cervix: A Case Report with Peculiar MRI Findings)

  • 황윤철;박서영
    • 대한영상의학회지
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    • 제83권3호
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    • pp.693-698
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    • 2022
  • 자궁 경부 혈관근종은 평활근 세포와 두꺼운 벽의 혈관으로 구성되어 있는 극히 드문 양성 종양이다. 현재 자궁 경부 혈관근종에 대한 증례 보고는 거의 없는 것으로 알려져 있다. 저자들은 38세 여성의 증례를 통하여 자궁 경부 혈관근종의 초음파, 조영증강 전산화단층촬영, 자기공명영상을 포함한 영상학적, 그리고 병리학적 소견에 대하여 보고하고자 한다.

상악동에 발생한 일차성 섬유질형 수막종: 증례 보고 및 문헌 고찰 (Primary Extracranial Fibrous Meningioma of the Maxillary Sinus: A Case Report and Literature Review)

  • 조현우;김상현;강명진;김동원
    • 대한영상의학회지
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    • 제82권1호
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    • pp.231-236
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    • 2021
  • 수막종은 중추신경계에서 흔한 종양이지만, 부비동, 특히 상악동에 위치한 일차성 두개외 수막종은 매우 드물다. 본 연구에서는 상악동에서 발생한 일차성 섬유질형 수막종의 증례를 보고하고, 문헌의 섬유질형 수막종의 영상 소견과 함께 고찰하고자 한다.

Stability of an improved optimization iterative algorithm to study vibrations of the multi-scale solar cells subjected to wind excitation using Series-Fourier algorithm

  • Jing Pan;Yi Hu;Guanghua Zhang
    • Steel and Composite Structures
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    • 제50권1호
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    • pp.45-61
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    • 2024
  • This research explores the domain of organic solar cells, a photovoltaic technology employing organic electronics, which encompasses small organic molecules and conductive polymers for efficient light absorption and charge transport, leading to electricity generation from sunlight. A computer simulation is employed to scrutinize resonance and dynamic stability in OSCs, with a focus on size effects introduced by nonlocal strain gradient theory, incorporating additional terms in the governing equations related to displacement and time. Initially, the Navier method serves as an analytical solver to delve into the dynamics of design points. The accuracy of this initial step is verified through a meticulous comparison with high-quality literature. The findings underscore the substantial impact of viscoelastic foundations, size-dependent parameters, and geometric factors on the stability and dynamic deflection of OSCs, with a noteworthy emphasis on the amplified influence of size-dependent parameters in higher values of the different layers' thicknesses.

MRI 영상획득 중의 피험자 움직임 감지 및 알림 시스템 (Head Motion Detection and Alarm System during MRI scanning)

  • 배종원;박해정;김대진
    • Investigative Magnetic Resonance Imaging
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    • 제16권1호
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    • pp.55-66
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    • 2012
  • 목적 : 자기공명영상(MRI) 획득시 피험자의 머리 움직임은 영상의 품질에 영향을 줄 수 있다. 영상 왜곡의 발생 원인이 되는 피험자의 움직임을 감지하기 위한 3차원 광학 추적 시스템을 제작하였다. 대상 및 방법 : 시스템은 두 대의 CCD 카메라 및 적외선 조명, 구형 반사 마커, 프레임 그래버(frame grabber)와 데스크탑 컴퓨터로 구성되었다. 두 대의 카메라를 이용하여 마커의 움직임을 관측하는 스테레오 비전 시스템을 제작하고, 카메라의 내부/외부 매개변수를 측정하는 캘리브레이션(calibration)과 측정된 매개변수를 이용하여 3차원 움직임 정보를 계산하는 삼각측량(triangulation)기법을 적용하였다. 캘리브레이션 보드와 피험자용 안경을 제작하여 움직임 추적의 정확도와 실제 MRI 영상 촬영 동안의 움직임 검출의 유효성을 평가하였다. 결과 : 반사 마커가 부착된 안경을 쓴 피험자들이 MRI 영상 촬영 동안 머리를 규칙적으로 움직였을 때, 시스템은 MRI의 고자장 환경 내에서도 영상에 영향을 주지 않고 피험자들의 움직임을 잘 감지했다. 결론 : 제작한 스테레오 비전 시스템은피험자의 머리 움직임을 잘 감지하였고, 실시간 알림 기능을 통해 피험자의 움직임을 중지할 수 있도록 알려줌으로써 MRI 영상에 영향을 주는 것을 최소화할 수 있다.