• Title/Summary/Keyword: Dominant frequency

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A Review on factors that influence Electrogastrography (위전도(胃電圖)에 영향을 미치는 요인(要因)에 대한 고찰(考察))

  • Kim, Sun-Hyeok;Park, Young-Bae;Park, Young-Jae;Oh, Hwan-Sup
    • The Journal of the Society of Korean Medicine Diagnostics
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    • v.13 no.1
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    • pp.10-18
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    • 2009
  • Objectives : To review to determine difference in the effect of age, gender, location of electrode, test meal and period of recording that influence Electrogastrography (EGG) parameters and to study its oriental medical application. Methods : We investigate the research results through internet search engines, Pub Med, Karger, Mary Ann Libert and Pro Quest. Results : Age and gender influence postprandial Dominant Frequency Instability Coefficient (DFIC). Body mass index (BMI) influence fasting and postprandial EGG parameters. Menstrual cycle phase influence fasting Dominant Frequency (DF). Test meal volume and composition influence postprandial EGG parameters. But reduced-calorie test meal have no effect on EGG parameters. Conclusions : Because the amplitude of surface-recorded SW(slow wave) is very weak, EGG is influenced by many factors. Age, gender, BMI, menstrual cycle phase, test meal volume and test meal composition influence EGG parameters. but reduced-calorie test meal have no effect on EGG parameters.

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Elastic Wave Characteristics of Incoloy 825 with Different Solution Treatment Temperature and Aging Time (용체화처리 온도 및 시효 시간이 다른 Incoloy 825의 탄성파 특성)

  • Lee, Seong-Gu;Choi, Byoung-Chul;Nam, Ki-Woo
    • Journal of the Korean Society of Industry Convergence
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    • v.24 no.3
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    • pp.261-269
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    • 2021
  • This study was evaluated the elastic wave properties according to tension of Incoloy 825 alloy with different solution treatment temperature and aging time. Solution treatment was carried out at 700, 800, 900, and 1000 ℃ for 1 hour, and aging was carried out at 700 ℃ for 1, 5, 10, and 30 hours. As the solution treatment temperature increased, the tensile strength decreased and the elongation increased. However, as the aging time increased, the tensile strength increased and the elongation decreased. The dominant frequency decreased as the solution treatment temperature increased, but increased as the aging time increased. The dominant frequency according to the solution treatment and aging time increased as the tensile strength increased, but increased despite the decrease in elongation.

Normalization Effect of Both ST36 and CV11, 12, 13 Meridian Points on the Abnormal Gastric Myoelectrical Activity in Two Cases of Functional Dyspeptic Patients (족삼리와 상완, 중완, 하완혈의 침 자극으로 기능성 소화불량증 환자의 위 평활근 전기적 활성 장애를 정상화시켰던 증례 2례)

  • Yoon, Sang-Hyub
    • The Journal of Internal Korean Medicine
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    • v.42 no.4
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    • pp.707-717
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    • 2021
  • Objectives: The aim of this study was to introduce the normalization effects of stimulation of both ST36 and CV11, 12, 13 meridian points on the abnormal gastric myoelectrical activity in two cases of functional dyspeptic patients with gastric dysmotility. Methods: Gastric myoelectrical activity was recorded by electrogastrography every two weeks until their gastric myoelectrical activity finally reached the normality. Dominant frequency of gastric slow waves in the fasting and postprandial periods and a dominant power ratio were obtained on each occasion. Patients were treated three times each day: 9 am, 1 pm, and 7 pm. The first treatment consisted of manual and immersion stimulation on all used meridian points for 20 min. In the second and third treatments, electrical stimulation of both ST36 was added. It was conducted for 20 min at a strength intensity of 1.2 times the pain threshold at a frequency of 3 Hz. Results: Stimulation of the above meridian points normalized abnormal gastric myoelectrical activity. The time taken to return from abnormal gastric myoelectrical activity to normal was 16-19 weeks. Conclusion: Stimulation of both ST36 and CV11, 12, 13 meridian points normalized the abnormal gastric myoelectrical activity in the functional dyspepsia of gastric dysmotility.

Condensation oscillation characteristic of steam with non-condensable gas through multi-hole sparger at low mass flux

  • Dandi Zhang;Lili Tong;Xuewu Cao
    • Nuclear Engineering and Technology
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    • v.55 no.2
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    • pp.780-791
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    • 2023
  • To study oscillation characteristic of steam and non-condensable gas direct contact condensation through multi-hole sparger at low mass flux, a series of experiments of pure steam and mixture gas condensation have been carried out under the conditions of steam mass flux of 20-120kg/m2s, water temperature of 20-95 ℃ and mass fraction of non-condensable gas of 0-5%. The regime map of pure steam condensation through multi-hole sparger is divided into steam chugging, separated bubble, aggregated bubble and escaping aggregated bubble. The bubbles behavior of synchronization in the same hole columns and desynchronized excitation between different hole columns can be found. The coalescence effect of mixture bubbles increases with water temperature and non-condensable gas content increasing. Pressure oscillation intensity of pure steam condensation first increases and then decreases with water temperature increasing, and increases with steam mass flux increasing. Pressure oscillation intensity of mixture gas condensation decreases with water temperature and non-condensable gas content increasing, which is significantly weaker than that of pure steam condensation. The oscillation dominant frequency decreases with the rise of water temperature and non-condensable gas content. The correlations for oscillation intensity and dominant frequency respectively are developed in pure steam and mixture gas condensation at low mass flux.

Vibration Characterization of Cross-ply Laminates Beam with Fatigue Damage (피로 손상을 입은 직교 복합재료 적층보의 진동 특성)

  • 문태철;김형윤;황운봉;전시문;김동원;김현진
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.05a
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    • pp.1-4
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    • 2001
  • A new non-destructive fatigue prediction model of the composite laminates is developed. The natural frequencies of fatigue-damaged laminates under extensional loading are related to the fatigue lift of the laminates by establishing the equivalent flexural stiffness reduction as a function of the elastic properties of sublaminates. The flexural stiffness is derived by relating the $90^{\circ}$-ply elastic modulus reduction, and using the laminate plate theory to the degraded elastic modulus and the intact elastic modulus of other laminate. The natural frequency reduction model, in which the dominant fatigue mode can be identified from the sensitivity scale factors of sublaminate elastic properties, provides natural frequency vs. fatigue cycle curves for the composite laminates. Vibration tests were also conducted on $[\textrm{90}_{2}\textrm{0}_{2}]_s$ carbon/epoxy laminates to verify the natural frequency reduction model. Correlations between the predictions of the model and experimental results are good.

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A forensic study of the Lubbock-Reese downdraft of 2002

  • Holmes, J.D.;Hangan, H.M.;Schroeder, J.L.;Letchford, C.W.;Orwig, K.D.
    • Wind and Structures
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    • v.11 no.2
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    • pp.137-152
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    • 2008
  • This paper discusses engineering aspects of the rear-flank downdraft that was recorded near Lubbock, Texas on 4 June 2002, and produced a gust wind speed nearly equal to the design value (50-year return period) for the region. The general characteristics of the storm, and the decomposition of the time histories into deterministic 'running mean' and random turbulence components are discussed. The fluctuating wind speeds generated by the event can be represented as a dominant low-frequency 'running mean' with superimposed random turbulence of higher frequencies. Spectral and correlation characteristics of the residual turbulence are found to be similar to those of high-frequency turbulence in boundary-layer winds. However, the low-frequency components in the running-mean wind speeds are spatially homogeneous, in contrast to the low-frequency turbulence found in synoptic boundary-layer winds. With respect to transmission line design, this results in significantly higher 'span reduction factors'.

An Experimental Study on Wave Focusing Efficiency in the Generation of Directional Extreme Waves (파랑집중에 의한 다방향 극한파 생성의 효율성에 관한 실험적 연구)

  • 홍기용;류슈쉐;양찬규
    • Journal of Ocean Engineering and Technology
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    • v.16 no.5
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    • pp.1-6
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    • 2002
  • Extreme waves are generated in a model basin based on directional wave focusing. The targeted wave field is described by double summation method and it is applied to serpent-type wavemaker system. The extreme crest amplitude at a designed location is obtained by syncronizing the phases and focusing the directions of wave components. Two distinguished spectrums of constant wave amplitude and constant wave steepness are adapted to describe the frequency distribution of component waves. The surface profile of generated wave packets is measured by wave guage array and the effects of dominant spectral parameters governing extreme wave characteristics are investigated. It is found that frequency bandwidth, center frequency, shape of frequency spectrum and directional range play a significant role in the wave focusing. In particular, the directional effect significantly enhances the wave focusing efficiency.

Spatiotemporal Behaviors of Excited Xenon Atoms in a Three-Dimensional Diagnosable Microplasma Unit Cell with High Sustain Frequency for Plasma Display Panels

  • Oh, Jun-Seok;Sakai, Osamu;Hashimoto, Masaki;Tachibana, Kunihide
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.925-928
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    • 2006
  • With the high sustain frequency at 250 kHz, a three-dimensional diagnostics of excited xenon atoms was investigated by the emission and absorption microscopic spectroscopy for plasma display panels, spatiotemporally. As a typical feature of the emissions, a broad discharge peak was observed on the temporal cathode and a sharp one was monitored on the anode, at the high frequency. However, the discharge starts from the cathode edge, actually, that is a discharge space on the floated address (or data) electrode. Spatially, the dense emission and absorption peak were observed in the discharge space between the sustain electrodes gap. Overall, the microdischarge at high sustain frequency showed priming dominant characteristics.

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Variation of the Sound Insulation Performance of Window in the Apartment House depending on the Sound Source Characteristics (공동주택에서 음원특성에 따른 외부창호 차음성능 변화)

  • Park, Hyeon-Ku;Lee, Ok-Kyun;Han, Dong-Hwa;Song, Hyuk;Kim, Sun-Woo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.1735-1740
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    • 2000
  • The aim of this study is to analyze the sound insulation performance of windows depending on the sound source types and to propose the noise control method in the apartment house. The regions where apartment houses are constructed are varied in the dominant noise sources such as aircraft noise, railway noise and road traffic noise. For the experiment, nine noise sources including pink noise were selected and recorded, which was used in the experiment by reproducing. As a result of this study, the sound insulation performance of window was found that when the frequency contents of the noise were high level in all frequency bands the difference of sound insulation performance was negligible, but when the frequency contents were low level at particular frequency band the difference of sound insulation performance was shown very differently.

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The research of vibration power generation to make effective use of ocean wave energy (파도에너지를 효율적으로 이용하기위한 파력진동발전기에 대한 연구)

  • Lee, Hong-Chan;Lee, Jae-Ho;Han, Ki-Bong
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2011.10a
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    • pp.75-75
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    • 2011
  • This paper has been studied that ocean wave vibration power generator is composed of buoy and vibration generator to make effective use of ocean wave energy. We designed buoy to can occur resonance for dominant frequency with ocean wave. And then we fitted the natural frequency of vibration system with vibration power generator to buoy's natural frequency. And we can show that the amplitude of ocean wave up and down motion is decreased, on the other hand, the displacement of vibration system with vibration power generator is increased. Therefore, ocean wave vibration power generator which is proposed in this paper has merits not only securing its stability from surroundings but also producing more electronic power by using ocean wave energy.

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