• Title/Summary/Keyword: P-waves

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P- and S-wave seismic studies in the Ulsan fault zone near Nongso-Eup (농소읍 부근 울산단층대에서의 P파 및 S파 탄성파 조사 연구)

  • Lee, Chang-Min;Kim, Ki-Young
    • 한국지구물리탐사학회:학술대회논문집
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    • 2006.06a
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    • pp.95-100
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    • 2006
  • To reveal subsurface structures of the Ulsan fault, seismic data were recorded along a 750-m long line near Nongso-Eup in Ulsan. P and S waves were generated simultaneously by impacting a 5 kg sledgehammer on a tilted plate. The data were received by 16 10-Hz 3-component geophones at 3 m intervals. Refracted P waves were inverted using the tomography method. Dip moveout and migration were applied to reflection data processed following a general sequence. Four layers were identified based on P-wave velocities and P- and S-wave stacked image. From top to bottom, the P-wave velocity of each layer ranges in $300{\sim}1100\;m/s$, $1100{\sim}1700\;m/s$, $1700{\sim}2700\;m/s$, and greater than 2700 m/s. The corresponding thickness of the top three layers averages 3.9 m, 5.9 m, 4.4 m, respectively. The S-wave stack section is effective to define subsurface structures shallower than 10 m.

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TRPC4 Is an Essential Component of the Nonselective Cation Channel Activated by Muscarinic Stimulation in Mouse Visceral Smooth Muscle Cells

  • Lee, Kyu Pil;Jun, Jae Yeoul;Chang, In-Youb;Suh, Suk-Hyo;So, Insuk;Kim, Ki Whan
    • Molecules and Cells
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    • v.20 no.3
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    • pp.435-441
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    • 2005
  • Classical transient receptor potential channels (TRPCs) are thought to be candidates for the nonselective cation channels (NSCCs) involved in pacemaker activity and its neuromodulation in murine stomach smooth muscle. We aimed to determine the role of TRPC4 in the formation of NSCCs and in the generation of slow waves. At a holding potential of -60 mV, $50{\mu}M$ carbachol (CCh) induced $I_{NSCC}$ of amplitude [$500.8{\pm}161.8pA$ (n = 8)] at -60 mV in mouse gastric smooth muscle cells. We investigated the effects of commercially available antibodies to TRPC4 on recombinant TRPC4 expressed in HEK cells and CCh-induced NSCCs in gastric smooth muscle cells. TRPC4 currents in HEK cells were reduced from $1525.6{\pm}414.4pA$ (n = 8) to $146.4{\pm}83.3pA$ (n = 10) by anti-TRPC4 antibody and $I_{NSCC}$ amplitudes were reduced from $230.9{\pm}36.3pA$ (n = 15) to $49.8{\pm}11.8pA$ (n = 9). Furthermore, $I_{NSCC}$ in the gastric smooth muscle cells of TRPC4 knockout mice was only $34.4{\pm}10.4pA$ (n = 8) at -60 mV. However, slow waves were still present in the knockout mice. Our data suggest that TRPC4 is an essential component of the NSCC activated by muscarinic stimulation in the murine stomach.

Physiological and psychological effects of forest healing focused on plant fragrance therapy for maladjusted soldiers

  • Kim, Jihye;Sin, Changseob;Park, Jong-ok;Lee, Hyunchae;Kim, Jihye;Kim, Dohyeong;Kim, Sanghee
    • Journal of People, Plants, and Environment
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    • v.24 no.4
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    • pp.429-439
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    • 2021
  • Background and objective: This study verified the physiological and psychological effects of plant fragrance therapy to analyze whether the therapy has a forest healing effect on maladjusted soldiers. Methods: This study was conducted from March 14 to May 31, 2020 according to the Green Camp curriculum for 2 weeks per recruit class. Thus, plant fragrance therapy was implemented twice each for three recruit classes. Each session of the program was carried out for 4 hours from 1 p.m. to 5 p.m. The venue was the garden within the camp and the forest nearby. Forest healing activities using plant fragrances were led by 1 forest education specialist and 1 assistant. The effects of plant fragrance therapy for maladjusted soldiers were analzed analyzed by quantifying physiological and psychological changes through measuring brain waves and stress levels before and after the therapy. Results: As a result of analyzing BRQ and SQ to determine the physiological and psychological healing effect of plant fragrance therapy, both the left and right brain showed higher BRQ and SQ after the therapy with statistical significance. This indicates that plant fragrance therapy on maladjusted soldiers helped positively stabilize their negative psychological and behavioral dispositions, and stabilization of brain waves lowered physical and mental stress and improved self-regulation and immunity. On the other hand, there was no significant difference in ATO. This is the result of analyzing the stress-coping mechanism. Troubleshooting (t = -2.702, df = 61, p = .009), emotional remission (t = -2.173, df = 61, p = .034), pursuit of help (t = -3.286), df = 61, p = .002), and wishful thinking (t = -3.714, df = 61, p < .001) showed statistically significant results. Conclusion: Applying plant fragrance therapy to maladjusted soldiers positively stabilized their negative psychological and behavioral dispositions and helped their self-regulation. Thus, plant fragrance therapy has psychological and physical forest healing effect on maladjusted soldiers.

Effects of Sleep Habits on EEG Sensory Motor Rhythm in Female College Students (여자 대학생의 수면습관이 감각운동리듬 뇌파에 미치는 영향)

  • Lee, Won-Joon;Choi, Hyun-Ju
    • Journal of Life Science
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    • v.22 no.5
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    • pp.613-620
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    • 2012
  • To evaluate the effects of sleep habits on the powers of beta waves and the sensory motor rhythm of the electroencephalogram (EEG), female college student subjects were divided into four groups, according to their sleep habits, as follows: GSHG (Good Sleep Habit Group), CSHG (Common Sleep Habit Group: late bedtime), CSDG (Cognitive Sleep Disorder-Delayed Sleep Phase Syndrome Group), and NSDG (Non-cognitive Sleep Disorder-Delayed Sleep Phase Syndrome Group). Brain function was stimulated by reading a book for 3 min in the morning (9~12 am) and the EEG was measured. According to the results, the powers of the beta waves and sensory motor rhythm were not different during the resting period among the four groups. However, during the reading stimulation period, the powers of beta waves and the sensory motor rhythm in the GSHG were significantly greater than in the other groups ($p$ <0.05). Beta powers during stimulation also increased in all brain areas in the GSHG ($p$ <0.05). Interestingly, these were decreased in the frontal and temporal lobes in the CSHG by the reading stimulation ($p$ <0.05). On the other hand, sensory motor rhythm, which represents focusing efficacy, only improved in the GSHG. These results indicate that the brain's focusing function during the reading stimulation was not properly operating in the morning in the female college students who had a delayed bedtime and bad sleep habits.

Inner harbour wave agitation using boussinesq wave model

  • Panigrahi, Jitendra K.;Padhy, C.P.;Murty, A.S.N.
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.1
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    • pp.70-86
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    • 2015
  • Short crested waves play an important role for planning and design of harbours. In this context a numerical simulation is carried out to evaluate wave tranquility inside a real harbour located in east coast of India. The annual offshore wave climate proximity to harbour site is established using Wave Model (WAM) hindcast wave data. The deep water waves are transformed to harbour front using a Near Shore spectral Wave model (NSW). A directional analysis is carried out to determine the probable incident wave directions towards the harbour. Most critical threshold wave height and wave period is chosen for normal operating conditions using exceedence probability analysis. Irregular random waves from various directions are generated confirming to Pierson Moskowitz spectrum at 20m water depth. Wave incident into inner harbor through harbor entrance is performed using Boussinesq Wave model (BW). Wave disturbance experienced inside the harbour and at various berths are analysed. The paper discusses the progresses took place in short wave modeling and it demonstrates application of wave climate for the evaluation of harbor tranquility using various types of wave models.

Preliminary numerical study on long-wavelength wave propagation in a jointed rock mass

  • Chong, Song-Hun;Kim, Ji-Won;Cho, Gye-Chun;Song, Ki-Il
    • Geomechanics and Engineering
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    • v.21 no.3
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    • pp.227-236
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    • 2020
  • Non-destructive exploration using elastic waves has been widely used to characterize rock mass properties. Wave propagation in jointed rock masses is significantly governed by the characteristics and orientation of discontinuities. The relationship between spatial heterogeneity (i.e., joint spacing) and wavelength for elastic waves propagating through jointed rock masses have been investigated previously. Discontinuous rock masses can be considered as an equivalent continuum material when the wavelength of the propagating elastic wave exceeds the spatial heterogeneity. However, it is unclear how stress-dependent long-wavelength elastic waves propagate through a repetitive rock-joint system with multiple joints. A preliminary numerical simulation was performed in in this study to investigate long-wavelength elastic wave propagation in regularly jointed rock masses using the three-dimensional distinct element code program. First, experimental studies using the quasi-static resonant column (QSRC) testing device are performed on regularly jointed disc column specimens for three different materials (acetal, aluminum, and gneiss). The P- and S-wave velocities of the specimens are obtained under various normal stress levels. The normal and shear joint stiffness are calculated from the experimental results using an equivalent continuum model and used as input parameters for numerical analysis. The spatial and temporal sizes are carefully selected to guarantee a stable numerical simulation. Based on the calibrated jointed rock model, the numerical and experimental results are compared.

Harmonic seismic waves response of 3D rigid surface foundation on layer soil

  • Messioud, Salah;Sbartai, Badredine;Dias, Daniel
    • Earthquakes and Structures
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    • v.16 no.1
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    • pp.109-118
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    • 2019
  • This study, analyses the seismic response for a rigid massless square foundation resting on a viscoelastic soil layer limited by rigid bedrock. The foundation is subjected either to externally applied forces or to obliquely incident seismic body or surface harmonic seismic waves P, SV and SH. A 3-D frequency domain BEM formulation in conjunction with the thin layer method (TLM) is adapted here for the solution of elastodynamic problems and used for obtained the seismic response. The mathematical approach is based on the method of integral equations in the frequency domain using the formalism of Green's functions (Kausel and Peck 1982) for layered soil, the impedance functions are calculated by the compatibility condition. In this study, The key step is the characterization of the soil-foundation interaction with the input motion matrix. For each frequency the impedance matrix connects the applied forces to the resulting displacement, and the input motion matrix connects the displacement vector of the foundation to amplitudes of the free field motion. This approach has been applied to analyze the effect of soil-structure interaction on the seismic response of the foundation resting on a viscoelastic soil layer limited by rigid bedrock.

Effects of Cranial Electrotherapy Stimulation on Electrocephalogram

  • Lee, Jeongwoo;Lee, Hyejein;Park, Woongsik
    • Journal of International Academy of Physical Therapy Research
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    • v.10 no.1
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    • pp.1687-1694
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    • 2019
  • Background: Although cranial electrotherapy stimulation (CES) is reported to have positive effects on mental functions such as depression and sleep improvement, detailed studies regarding awakening, attention and concentration among brain waves reflecting brain activity are lacking. Objective: To examine the effects of cranial electrotherapy stimulation (CES) on various electroencephalograms (EEGs) reflecting brain activities. Design: Randomized controlled clinical trial (single blind) Methods: This study selected 30 healthy adult women in their 20s who volunteered for this experiment. A total of 30 subjects were randomly assigned to three groups (Sham group, 0.5 Hz CES group, and 100 Hz CES group). EEGs were measured before and after the single CES, and the results were compared and analyzed. Results: The relative theta, alpha, and gamma waves indicated no significant differences in the interaction effects between time and group. The relative fast alpha wave only showed significant differences in the interaction effects between time and group in P4. The relative slow beta wave only indicated statistically significant differences in the interaction effects between time and group in T3 and T4. The relative mid and fast beta waves showed statistically significant differences in the interaction effects between time and group in all areas. Conclusions: These results suggest that a CES of 0.5 Hz awakens consciousness and has a positive influence on brain activity, while a CES of 100 Hz has a positive influence on thinking activity accompanying mental load during concentrating on one subject.