• Title/Summary/Keyword: Resonance condition

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On Installation of Bus Trunk System for Wind Tower (풍력타워용 부스닥트 포설시스템 개발)

  • Lee, Joon-Keun;Kim, Bong-Seok;Park, Seong-Hee;Ahn, Hyung-Joon;Lee, Hee-Nam
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.330-335
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    • 2012
  • A Bus Trunk System for Wind Tower is introduced. A marine cable has been widely used in wind tower or other offshore structure. However, as the electric load capacity is getting increased, the large number of cable lines should be used to cover such a huge amount of electric capacities, which makes the installation make quite difficult due to the heavy weight and volume of the present cables. On the other hand, by using a single bus trunk system line, the power capacity amount of 16 number of cable can be delivered with significant compactness. However, unlike flexible cable, the bus trunk is relatively stiff which could arise resonance phenomenon in the operating condition of wind tower, therefore, the vibration characteristics of bus trunk should be investigated and verify its long-term reliability during the life time of the wind tower.

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PHOTOLYSIS OF [1.1.1]PROPELLANE : SYNTHESIS OF NEW COMPOUNDS AND MECHANISTIC STUDY

  • Lee, Woo-Bung;Oh, Dong-Won;Park, Mi-Sook;Hwang, Dug-Hea;Cheong, Chae-Joon;Moon, Hong-Young
    • Journal of Photoscience
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    • v.6 no.2
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    • pp.57-60
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    • 1999
  • The reaction of [1.1.1]propellane with singlet methylene afforded 1,3-dimethylenecyclobutane and [l.1.1.1]paddlane (3). Various minor products were also produced. The reaction of [1.1.1]propellane with triplet methylene afforded 1,3-dimethylenecyclobutane (2) and various minor products. But even trace of [1.1.1.1]paddlane was not detected. The mechanism for the addition of singlet methylene involved [1.1.1.1]paddlane intermediate The addition of triplet methylene led to diradical intermediate. In order to reveal the reaction pathway for generation of various ruiner products, various studies were carried out under the same condition.

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Traumatic Spinal Subdural Hematoma Accompanying intracranial hematoma: Spontaneous Resolution after Pumbar Puncture (외상성 구개강내 출혈과 동반된 척추경막하 출혈; 요추 전자부 자연흡수)

  • Lee, Won Tae;Kim, Seok Won
    • Journal of Trauma and Injury
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    • v.19 no.1
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    • pp.93-96
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    • 2006
  • A traumatic spinal subdural hematoma is a rare condition, and only nine cases have been reported until now. We report a rare case of concomitant intracranial hemorrhage and spinal subdural hematoma with a review of the literature. A 45-year-old man was referred to our institute after being stroke by a car. He complained of nausea, headache, back pain, and bilateral sciatica. Brain computed tomography and lumbar spine magnetic resonance images revealed both an intracerbral hemorrhage and a subdural hematoma in the L4 to S1 level. After performing a lumbar spinal puncture and draining the hemorrhagic cerebrospinal fluid (CSF), the intracranial and spinal hematomas were resolved completely without any neruologic deficits.

Pseudoaneurysm with Arteriovenous Fistula after Arthroscopic Procedure: A Rare Complication of Arthroscopy

  • Jin, Moran;Lee, Yang-Haeng;Yoon, Young Chul;Han, Il-Yong;Park, Kyung-Taek;Wi, Jin Hong
    • Journal of Chest Surgery
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    • v.48 no.4
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    • pp.302-305
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    • 2015
  • Pseudoaneurysm with arteriovenous fistula is a rare complication of arthroscopy, and can be diagnosed by ultrasonography, computed tomography, magnetic resonance imaging, or angiography. This condition can be treated with open surgical repair or endovascular repair. We report our experience with the open surgical repair of a pseudoaneurysm with an arteriovenous fistula in a young male patient who underwent arthroscopy five months previously.

Stress Fracture of the First Rib (제1늑골의 피로골절)

  • Choi, Soo-Seung;Yoo, Jeong-Hyun
    • Journal of Chest Surgery
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    • v.42 no.5
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    • pp.674-676
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    • 2009
  • Isolated stress fracture of the first rib is rare, and repeated muscular pulling and fatigue of bone is thought to be responsible for this fracture. The diagnosis can be made by taking a thorough history and performing chest roentgenography, computed tomography or magnetic resonance imaging. Conservative treatment generally cures this condition. We report here on a case of exercise-induced isolated stress fracture of the first rib in a non-athlete college student and we review the related articles.

Painless Aortic Dissection Simulating Guillain-Barré Syndrome (길랑-바레 양상으로 발현한 무통성 대동맥 박리 1례)

  • Oh, Eun-Jin;Jeong, Sang-Wuk;Park, Jong-Kwan;Hong, Keun-Sik
    • Annals of Clinical Neurophysiology
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    • v.7 no.1
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    • pp.49-51
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    • 2005
  • A 61-year-old man with an antecedent febrile illness presented with progressive flaccid paraparesis, but no sensory or sphincter involvement. Magnetic resonance imaging (MRI) of the spine was negative and nerve conduction study (NCS) showed the absence of F-waves in his legs, suggesting $Guillain-Barr{\acute{e}}$ syndrome (GBS). However, abdominal pain after admission led to the consideration of the spinal cord ischemia secondary to aortic dissection confirmed by computed tomography. We report the rare condition of painless aortic dissection simulating GBS.

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Spontaneous Spinal Subdural Hematoma Concurrent with Cranial Subdural Hematoma

  • Moon, Wonjun;Joo, Wonil;Chough, Jeongki;Park, Haekwan
    • Journal of Korean Neurosurgical Society
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    • v.54 no.1
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    • pp.68-70
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    • 2013
  • A 39-year old female presented with chronic spinal subdural hematoma manifesting as low back pain and radiating pain from both legs. Magnetic resonance imaging (MRI) showed spinal subdural hematoma (SDH) extending from L4 to S2 leading to severe central spinal canal stenosis. One day after admission, she complained of nausea and severe headache. Computed tomography of the brain revealed chronic SDH associated with midline shift. Intracranial chronic SDH was evacuated through two burr holes. Back pain and radiating leg pain derived from the spinal SDH diminished about 2 weeks after admission and spinal SDH was completely resolved on MRI obtained 3 months after onset. Physicians should be aware of such a condition and check the possibility of concurrent cranial SDH in patients with spinal SDH, especially with non-traumatic origin.

Hypertensive Encephalopathy with Reversible Brainstem Edema

  • Lee, Sungjoon;Cho, Byung-Kyu;Kim, Hoon
    • Journal of Korean Neurosurgical Society
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    • v.54 no.2
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    • pp.139-141
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    • 2013
  • Presented here is a 36-year-old male with arterial hypertension who developed brainstem edema and intracranial hemorrhage. Magnetic resonance scan revealed diffuse brainstem hyperintensity in T2-weighted and fluid-attenuated inversion-recovery images, with an increase in apparent diffusion coefficient values. After a reduction in blood pressure, rapid resolution of the brainstem edema was observed on follow-up. The patient's condition was thus interpreted as hypertensive brainstem encephalopathy. While many consider this a vasogenic phenomenon, induced by sudden, severe hypertension, the precise mechanism remains unclear. Prompt recognition and aggressive antihypertensive treatment in such patients are essential to prevent permanent or life-threatening neurologic injury.

Carotidynia presenting with acute ischemic stroke after carotid sinus massage

  • Kwak, Hyo Sung;Chung, Gyung Ho;Lee, Chan-Hyuk;Jeong, Seul-Ki;Ryu, Han Uk
    • Annals of Clinical Neurophysiology
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    • v.19 no.1
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    • pp.46-49
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    • 2017
  • Carotidynia is characterized by unilateral neck pain around the carotid artery. We describe a 50-year-old woman who presented with transient left-side weakness and right-side neck pain. She frequently massaged the uncomfortable neck area during the symptomatic course of the condition. Magnetic resonance imaging revealed multifocal cerebral infarctions and a carotid intramural thrombus ipsilateral to the carotidynia.Long-term carotidynia might result in the involvement of an intramural thrombus and intimal disruption, and ischemic stroke after carotidynia may be provoked by carotid sinus massage.

The Study on the Improvement on Damping Ratio of Dynamic Absorber using Silicon Oil (실리콘 오일을 이용한 동흡진기 감쇠 성능 향상에 대한 연구)

  • Kwak, Y.S.;Kim, W.H.;Joo, W.H.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.113-118
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    • 2011
  • Many kinds of dynamic absorbers have been used to reduce the vibration of machineries and structures. In the typical ones, however low damping capacity, durability and limited install condition restrict their application. In this study, high damped dynamic absorber was proposed for diesel generator set. Developed absorber is composed with mass and coil springs. Silicone oil was filled inside the narrow gap between mass and casing. Viscous damping of silicon oil act as additional damping so that proposed dynamic absorber is suitable for D/G set which have adjacent resonance frequency to operation speed. The performance of the dynamic absorber was confirmed through the actual test on diesel engine generator set.

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