• Title/Summary/Keyword: 불안정운동

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DTERMINATION OF STBLE-UNSTABLE REGIONS OF THE SLOSH MOTION IN SPINNING SPACE VEHICLE BY PERTURBATION TECHNIQUE (PERTURBATION 방법을 이용한 회전안정화 우주비행체 내부 유동의 안정-불안정 영역 결정)

  • Kang, Ja-Young
    • Journal of Astronomy and Space Sciences
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    • v.22 no.4
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    • pp.513-526
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    • 2005
  • The objectives of this study are to perform extensive analysis on internal mass motion for a wider parameter space and to provide suitable design criteria for a broader applicability for the class of spinning space vehicles. In order to examine the stability criterion determined by a perturbation method, some numerical simulations will be performed and compared at various parameter points. In this paper, Ince-Strutt diagram for determination of stable-unstable regions of the internal mass motion of the spinning thrusting space vehicle in terms of design parameters will be obtained by an analytical method. Also, phase trajectories of the motion will be obtained for various parameter values and their characteristics are compared.

The effect of dynamic stabilization exercise on unstable surface on thickness, density of back muscle (불안정 지지면에서의 동적 안정화 운동이 허리근육의 두께 및 밀도에 미치는 효과)

  • Han, Jong-Man;Park, Jea-Cheol;Kim, Keum-Sook;Kim, Hyun-Ae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.3
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    • pp.1957-1963
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    • 2015
  • The purpose of this study is to examine the effect of dynamic stabilization exercise on unstable surface on thickness, muscle density and white area index (WAI) of transverse abdominis muscle and multifidus muscle. The subjects were 20s healthy adults and 27 people were measured for muscle thickness and muscle density, white area index after the experiment conducted during a six-week dynamic stabilization exercises divided into three groups, each in a different plane. The results showed a significant difference between the three groups (p <.05). Repeated measures analysis of variance (repeated ANOVA) results, transverse abdominis muscle and multifidus muscle thickness showed a significant difference between the groups in the time difference (p <.05), and between multifidus muscle density and white area index in the comparison between groups showed a significant difference (p <.05). In conclusion, showed significant difference in lumbar stabilization exercise part. These results seems to be utilized as a basis for future research on the lumbar stabilization exercise.

Full mouth rehabilitation using removable prosthesis of patient with unstable mandible movements: A case report (불안정한 하악운동을 보이는 환자에서 가철성 의치 수복 증례)

  • Sohn, Dong-Hwan;Yi, Yang-Jin;Jo, Deuk-Won
    • The Journal of Korean Academy of Prosthodontics
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    • v.58 no.1
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    • pp.35-41
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    • 2020
  • Patients with collapsed occlusal support and unilateral chewing show parafunctional mandibular movements, which can be complicated in older patients. Gothic arch tracing and split cast technique are used to confirm the deviation between centric relation and anterior habitual bite in patient who has oral dyskinesia and collapsed occlusion. Temporary denture as occlusal stabilization appliance was provided for stable occlusion and reproducible mandibular movement. Definitive denture was fabricated by lingualized occlusion concept.

가꾸는삶 - 병을 이기는 건강요가 - 편두통을 다스리는 요가 -

  • Jeong, Yu-Gyeong
    • 건강소식
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    • v.33 no.12
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    • pp.30-31
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    • 2009
  • 최근 극심한 불황으로 두통이나 편두통이 발생하여 병원을 찾는 사람이 2006년에 비해서 2008년에는 19.5%가 증가하였다고 한다. 편두통은 생활의 불안정과 미래에 대한 불안감에 의해 스트레스가 극대화되고, 운동부족과 좋지 않은 자세 습관으로 근육과 혈관이 수축됨으로 인해 호르몬의 변화가 생기면서 유발된다. 증상에 대한 회복을 위해서는 마음가짐을 편안히 하고 규칙적인 식사와 꾸준한 운동이 필수라고 할 수 있다.

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Investigation of Premixed Flame Instability with Heat and Momentum Losses (열 및 운동량 손실이 예혼합화염의 연소불안정성에 미치는 영향에 관한 연구)

  • Kang Sang Hun;Baek Seung Wook;Im Hong Geun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.3
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    • pp.101-119
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    • 2005
  • For MEMS applications, the effects of the momentum and heat loss on the stability of laminar premixed flames in a narrow channel are investigated by high-fidelity numerical simulations. A general finding is that momentum loss promotes the Saffman-Taylor (S-T) instability which is additive to the Darrieus-Landau (D-L) instabilities, while the heat loss effects result in an enhancement of the diffusive-thermal (D-T) instability. These effects are also valid in nonlinear behavior of the premixed flame. The simulations of multiple cell interactions are also conducted with heat and momentum loss effects.

Comparison of Balance Ability on Lunge Exercise on BOSU Ball and Balance Pad (보수볼과 밸런스패드 위 런지운동 시 균형 능력 비교)

  • Dong-In Seo;Ye-Eun Ki;Su-Jin Kim;Yun-Ji Kim;Hee-Jun Kim;Su-Hwan Bae;Sin-Won Seok;Seung-Hyun Lee;Hye-Won Han;In-Hyouk Hyong
    • Advanced Industrial SCIence
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    • v.3 no.2
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    • pp.23-30
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    • 2024
  • This study aimed to examine the changes in dynamic balance exercises after performing lunge exercises on unstable surfaces and on the ground. Participants were divided into a BOSU training group, a balance pad training group, and a ground training group, and performed lunge exercises. As a result, the functional reach test significantly increased in both the BOSU training group and the ground training group, while the Y-balance test significantly increased only in the balance pad training group. No significant differences were found between the groups. Through this study, it was confirmed that although differences between lunge exercises on the ground and on unstable surfaces were not identified, lunge exercises do influence balance ability.

Combustion Instability modeling - 1D approach (연소불안정 모델링 - 1D 접근법 기반)

  • Kim, Daesik;Yoon, Myunggon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.65-67
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    • 2017
  • Various combustion modeling approaches have been developed and verified in a combustion system such as rockets, gas turbines, and so on. This study introduces basic theory and recent research activities on 1D network model where a system is divided into a series of acoustic element and mass/momemtum/energy conservations are applied in the component. Each component is connected to the neighboring ones with proper jump conditions. Flame transfer function and acoustic transfer function are determined and effects of the each function on the system instability is investigated.

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A Study on Phugoid Mode in Longitudinal Axis of T-50 (T-50 세로축 장주기 모드 운동 특성에 관한 연구)

  • Kim, Jong-Seop;Hwang, Byeong-Mun;Kim, Seong-Jun;Heo, Gi-Bong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.4
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    • pp.25-32
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    • 2006
  • An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The flight control system utilize RSS criteria in both longitudinal and lateral-directional axes to achieve performance enhancements and improve stability. The T-50 advanced trainer employs the RSS concept in order to improve the aerodynamic performance and the flight control law in order to guarantee aircraft stability. The longitudinal two modes are the short period with high frequency and the phugoid mode with low frequency. The design goals of longitudinal control laws is concerned with the short period damping and frequency optimization using lower order equivalent system and utilizing the requirement of MIL-F-8785C. Analysis of short period mode has been and continues to be performed This paper addresses the analysis of aircraft phugoid node characteristics such as damping, natural frequency, and analysis of aircraft pitch motion that impacted by angle of attack limiter and auto pitch attitude control law.