• Title/Summary/Keyword: Constriction

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A Study on the Characteristics of High-Current Arc Plasma Influenced by Axial Magnetic Field (축방향 자기장에 의한 대전류 아크 특성에 관한 연구)

  • Cho, S.H.;Lee, J.C.;Choi, M.J.;Kwon, J.R.;Kim, Y.J.
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2515-2518
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    • 2008
  • The vacuum interrupter (VI) is widely used in medium-voltage switching circuits due to its abilities and advantages as an environmental friendly circuit breaker. An understanding of the vacuum arc flow phenomena is very important for improving the performance of vacuum interrupter. In order to closely examine the vacuum arc phenomena, it is necessary to predict the magnetohydrodynamic (MHD) characteristics by the multidisciplinary numerical modeling, which is coupled with the electromagnetic and the thermal flow fields, simultaneously. In this study, we have investigated arc plasma constriction phenomena and an effect of AMF on the arc plasma with the high-current vacuum arcs for the cup-type AMF electrode by using a commercial finite element analysis (FEA) package, ANSYS. The simulation results applied with various AMFs and constant Joule heat generation show that strong axial magnetic field (AMF) permits the arc to be maintained in a diffused mode to a high-current vacuum arc. However, further studies are required on the two-way coupling method and radiation model for arc plasma in order to accomplish the advanced analysis method.

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Research trends of inhalation drug for asthma in complementary and alternative medicine (보완대체의학의 천식 흡입치료제 연구 동향)

  • Yang, Su-Young;Oh, Ji-Seok;Park, Yang-Chun;Oh, Young-Seon;Lee, Yong-Koo
    • Journal of Haehwa Medicine
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    • v.18 no.1
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    • pp.1-8
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    • 2009
  • This study analyzed the contents of the research papers of Complementary Medicine concerning the inhalation drug for asthma published in Pubmed during lately 10 years. As a result, the following conclusion was drawn. 1. There were 5 papers concerning 2 review articles, 2 experimental studies and 1 clinical study. 2. Interventions of research papers are glutathione, microorganism fermentation extract (EM-X), ginkgolide and compound Chinese herbal monomer recipe (ligustrazin, baicalin, ginkgolide). 3. There is no controlled study for effect of inhaled glutathione, on the contrary it induced bronchial constriction in sulfites sensitive asthmatics. 4. Inhalation of EM-X reduced airway hyper-reactivity and level of IL-4, IL-5 and IL-13 in OVA challenged asthmatic mice. 5. Ginkgolide nebulized inhalation reduced symptomatic scorings and eosinophil cationic protein, improved FEV1 and PEF. 6. Compound Chinese herbal monomer (CHM) recipe reduced blood eosinophil count, eosinophil count and total cell cound in BALF, depressed airway hyper-responsiveness and airway inflammation.

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Studies on the Chromosomes of Orthotera in Korea (2) (한국산 주혈류의 염색체에 관한 연구(2))

  • KANG, Yung-Sun;SON, Hong-Chong
    • The Korean Journal of Zoology
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    • v.2 no.2
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    • pp.15-24
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    • 1959
  • Concluding the result of this observation, authors obtained the table showing chromosome numbers which are consisted in each species as follow. Viewing on this result, authors recognized Acrididae are determined the sex with X-O type. 6 species of Family Acrididae and one species of Family Gryllotalpidae (on above table) had already calculated the number of chromosomes by some foreign observers. But another one species (Briodema tuberculatum dilatum STOLL) clarified by authors firstly in this observation. In 2nd spermatocyte of Trilophidia annulata YHUMBERG 1 to 3 Ist constriction satellites were observed, and each of the small bodies was connected with thin fibre and constituted with same or less breadth as the main chromosomes. If those are not the satellites, they should be the super-numerary chromosomes appearing a dot form. In this observation, among 48 species of Family Acrididae which have been found in Korea 18 species were calculated their chromosome numbers which were including 1 species calculated by authors newly. And authors have reobserved the chromosomes of Gryllotalpa africana PALISOT de BEUVOIS of Family Gryllotalpidae which was done by Japanese before.

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Clinical characteristics and treatment plan for patients with snoring and obstructive sleep apnea (코골이와 수면무호흡증 환자의 임상적 특징과 치료계획)

  • Jung, Jae-Kwang;Kim, Ki-Rim;Byun, Jin-Seok;Choi, Jae-Kap
    • The Journal of the Korean dental association
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    • v.53 no.4
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    • pp.249-258
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    • 2015
  • Snoring and obstructive sleep apnea are the representative sleep disordered breathings, caused by the temporary and repetitive constriction or obstruction of upper airway during sleep. They present with excessively vibratory noise and repetitive cease of respiration. These disorders commonly result in sleep disturbance and the subsequent daytime sleepiness, chronic fatigue. Furthermore, they can cause the serious and extensive complications including increased risk of hypertension, cardiac arrhythmia, cardiovascular disease, cerebrovascular accident, neurocognitive disturbance, traffic and occupational accidents, type II diabetes, childhood growth interruption, awakening headache and finally, relatively increased mortality rate. Because appropriate therapeutic intervention is best way for patients to relieve their symptoms and prevent their possible complications, it is very important for dentists to recognize their own role and responsibility in diagnosis and treatment of these disorders. For this, the present article provides the understanding of the clinical features, possible complications, various treatment modalities, and suitable treatment strategies for snoring and obstructive sleep apnea.

A literatual studies on the cataract, glaucoma, bluish glaucoma (內障, 綠風內障, 靑風內障에 대한 文獻的 考察)

  • Park, Se-bong;Ko, Woo-shin
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.12 no.1
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    • pp.254-267
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    • 1999
  • Based on the research of cataract, glaucoma, bluish glaucoma, we have abtained the following results. 1. Main etiologies of the cataract are deficiency of the liver and kidneys, main symptoms are no nebula, no pain, no tear and sometimes light blue and white vision appear. 2. Main etiologies of glaucoma are receives heat from the liver, stagnation of the liver and gall bladder etc, main symptoms are both forehead corner pull each ether, pain from eye ball to nasal septum, headache, extending pain of the eyes, sometimes red and white flower vision appear, etc. 3. main etiologies of the bluish glaucoma are melancholy, wrath, stagnation of the liver, internal damage, flaming up fire of the phlegm, deficiency of the liver, deficiency of blood, etc, main symptoms are numbness, visual field constriction, blindness, reduce of visual capacity, blue flower vision sometimes appear, etc. 4. Treatments are mainly uses nourish Um(陰) to reduce pathogenic fire, relieve stagnancy of Ki(氣) of the liver, nourish Um(陰) of the liver and kidneys, etc, acupuncture points are mostly contended arounded eyes such as BL10)(天柱), GV16(風府), LR3)(太衝), HT5)(通里) and in the case of nauses and vomitting PC6)(內關, ST36)(足三里) are included in addition to the above.

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Surgical treatment of chronic constrictive pericarditis: Report of 23 cases (만성 교약성 심낭염 (23례 수술 보고))

  • 박영관
    • Journal of Chest Surgery
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    • v.1 no.1
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    • pp.61-68
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    • 1968
  • In the 10 years from 1958 through 1968, 23 patients have undergone 24 times of operation for constrictive pericarditis at this department. Follow-up data were available for periods varying several months to almost 10 years from examination at this department or follow-up letters. There were 21 males and 2 females in this series. Range of the age varied from 2 years to 53 years. Seven cases were below 15 years of age. There were two hospital death, one expired two weeks and another four weeks after the pericardiectomy. In both of them, myocardial damage by disease process seemed to be major contributing factors. Clinical and histological study showed tuberculous origin in 12 cases, non-specific chronic infiammatory changes in 8 cases and in 3 cases previous pyogenic pericardial infection by staphylococcus preceded to the constriction. In 11 cases bone tissue was noted microscopically in the pericardium: Sixteen patients[70 %]had pleural effusions, five cases had bilateral, 6 right, and 5 left. Calcification was seen along cardiac border in 9 cases. In 15 catheterized patients, 6 showed pressure gradients between vena cava and right atrium, ranging from 6 mmHg to 10 mmHg. One case was reoperated 3 months after the original operation resulting in marked improvement. In this reoperated case the original pericardiectomy seemed to be incomplete. In 21 cases. excluding 2 hospital death, symptoms and physical findings improved markedly in every patient

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Articulatory robotics (조음 로보틱스)

  • Nam, Hosung
    • Phonetics and Speech Sciences
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    • v.13 no.2
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    • pp.1-7
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    • 2021
  • Speech is a spatiotemporally coordinated structure of constriction actions at discrete articulators such as lips, tongue tip, tongue body, velum, and glottis. Like other human movements (e.g., reaching), each action as a linguistic task is completed by a synergy of involved basic elements (e.g., bone, muscle, neural system). This paper discusses how speech tasks are dynamically related to joints as one of the basic elements in terms of robotics of speech production. Further this introduction of robotics to speech sciences will hopefully deepen our understanding of how speech is produced and provide a solid foundation to developing a physical talking machine.

Age and gender differences in the spectral characteristics of Korean sibilants

  • Kong, Eun Jong;Kang, Jieun
    • Phonetics and Speech Sciences
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    • v.13 no.1
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    • pp.37-44
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    • 2021
  • While recent acoustic studies have reported associations of fronted sibilants (fricatives /s s⁎/ and affricates /tɕ tɕ⁎/) with gender in Seoul Korean, there have not been any studies examining the relationship of the variants with adult speakers' ages. The current study analyzes sibilant productions from 39 adult speakers born between 1942 and 2008 (19 females) in terms of spectral peak frequencies (SPFs) in frication, an acoustic index of place of articulation (POA). The results indicate some phonetic contexts where higher sibilant SPFs, i.e., fronter POAs, are associated with younger adults and those fronted variants are realized in a gender-differentiated manner -- tense affricates and word-initial tense fricatives before /i/ in the females' productions, and word-medial tense fricatives before /a/ in the males' productions. The findings confirm that the distributions of the fronted sibilants are accounted for not only by the speakers' gender but also by their ages, indicating that the fronted variants are innovative forms of realizing sibilants in Seoul Korean. In addition, the current results convincingly show that the fronted sibilant variants are not mere reflections of individuals' physiological differences since they are not observed across all of the examined phonetic contexts.

ENHANCING TIG WELD PERFORMANCE THROUGH FLUX APPLICATION ATIG AND FBTIG PROCESSES

  • Marya, S.
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.70-75
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    • 2002
  • The penetration potential of TIG welding in one single run is limited, though the process itself generates high quality welds with good weld cosmetics. This is one of the main reasons, which has contributed to its development in high duty applications such as those encountered in aeronautical, aerospace, nuclear & power plant applications. For these applications, stainless steels, titanium k nickel based alloys are most often used. As these materials remain very sensible to weld heat input k atmospheric pollution, stringent processing conditions are imposed. For example welding of titanium alloys requires argon shielding of weld zone and for 5 mm thick plates multi-pass runs & filler additions are required. This multi-run operation not only raises the welding cost, but also increases defect risks. In recent years, extensive interest has been raised by the possibility to increase weld penetrations through flux applications & the process is designated ATIG-activated TIG, or FBTIG-flux bounded TIG. The improved welding performance of such flux assisted TIG is related to arc constriction and surface tension effects on weld pool. The research work by authors has lead to the formulation of welding fluxes for stainless steels k titanium alloys with TIG Process. These fluxes are now commercialized & some applications in industry have already been carried out. FBTIG for aluminum has been proposed with silica application for AC mode TIG welding. The paper highlights the fundamentals of flux role in TIG welding and illustrates some industrial applications.

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Empirical Study of Smart Safety System to Increase Construction Disaster Prevention Effect - Centered on Construction Machinery (건설 재해 예방효과 증대를 위한 스마트 안전 시스템 실증연구 - 건설기계 중심)

  • Seung-Yong Choi
    • Journal of the Society of Disaster Information
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    • v.19 no.2
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    • pp.421-431
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    • 2023
  • Purpose: The purpose of this study is to analyze the safety and disaster prevention effects of the Smart Safety System used to prevent safety accidents in construction machinery and demonstrate its safety. Method: Among construction machines, the behavioral patterns of workers according to the presence or absence of a smart safety system were analyzed for excavators with high risk and frequent accidents. Result: When the smart safety system was installed in the construction machine, the safety of workers from accidents caused by constriction and collision with the construction machine was secured. Conclusion: It is judged that the smart safety system installed in construction machinery can increase the effectiveness of disaster reduction and major disaster prevention related to construction machinery.