• Title/Summary/Keyword: Spontaneous

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Numerical Study on the Effects of Surface-Inhibitors for the Prevention of Spontaneous Combustion of the Coal Stockpile

  • Kim, Jae-Kwan;Park, Seok-Un;Jang, Ji-Hoon;Joo, Yong-Jin
    • KEPCO Journal on Electric Power and Energy
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    • v.6 no.3
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    • pp.289-296
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    • 2020
  • In this paper, the effects of the spontaneous combustion inhibitor on the surface of the coal stockpile in the coal yard was investigated by numerical analysis. First, the numerical analysis method of the present study was compared with the results of the previous study by analyzing the case in which the spontaneous combustion inhibitor was not applied, while the effects of spraying the spontaneous combustion inhibitor for the prevention of spontaneous combustion onto various areas and positions was also analyzed. As a result, the larger the application area of the spontaneous combustion inhibitor, then the more effective it is for preventing spontaneous combustion as it blocks the oxygen inflow into the coal stockpile, while, when spraying the spontaneous combustion inhibitor from the bottom of the coal stockpile, then the greater the effect it has on the prevention of spontaneous combustion. In conclusion, it was most effective to spray the spontaneous combustion inhibitor from the bottom of the coal stockpile up to about 30% of the height of the coal stockpile, when considering the economic aspect.

Spontaneous Vertigo (자발현훈)

  • Choi, Kwang-Dong;Kim, Ji Soo
    • Annals of Clinical Neurophysiology
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    • v.9 no.1
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    • pp.1-4
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    • 2007
  • Vertigo is an illusion of rotation, which results from an imbalance within the vestibular system. This review focuses on two common presentations of spontaneous vertigo: acute prolonged spontaneous vertigo and recurrent spontaneous vertigo. Common causes of acute prolonged spontaneous vertigo include vestibular neuritis, labyrinthitis, and brainstem or cerebellar stroke. The history and detailed neurological/neurotological examinations usually provide the key information for distinguishing between peripheral and central causes of vertigo. Brain MRI is indicated in any patient with acute vertigo accompanied by abnormal neurological signs, profound imbalance, severe headache, and central patterns of nystagmus. Recurrent spontaneous vertigo occurs when there is a sudden, temporary, and largely reversible impairment of resting neural activity of one labyrinth or its central connections, with subsequent recovery to normal or near-normal function. Meniere's disease, migrainous vertigo, and vertebrobasilar insufficiency (VBI) are common causes. The duration of the vertigo attack is a key piece of information in recurrent spontaneous vertigo. Vertigo of vascular origin, such as VBI, typically lasts for several minutes, whereas recurrent vertigo due to peripheral inner-ear abnormalities lasts for hours. Screening neurotological evaluations, and blood tests for autoimmune and otosyphilis are useful in assessment of recurrent spontaneous vertigo that are likely to be peripheral in origin.

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Numerical Study on the Effects of Surface-inhibitors on the Spontaneous Ignition of Coal Stockpile (저탄장 자연발화에 미치는 표면차단제 영향에 관한 수치 해석적 연구)

  • Kim, Jae-Kwan;Park, Seok-Un;Shin, Dong-ik
    • Fire Science and Engineering
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    • v.33 no.2
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    • pp.20-29
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    • 2019
  • In this paper, the effect of spontaneous combustion inhibitor on the surface of coal stockpile in coal yard was investigated by numerical analysis. First, the numerical analysis method of the present study was compared with the results of the previous study by analyzing the case where the spontaneous combustion inhibitor was not applied, and the effect of preventing spontaneous combustion by various areas and positions for spraying spontaneous combustion inhibitor was analyzed. As a result, the larger the application area of the spontaneous combustion inhibitor, the more the effect of preventing spontaneous combustion by blocking the oxygen inflow into the coal stockpile, and the greater the effect of the spontaneous combustion prevention when spraying spontaneous combustion inhibitor from the bottom of the coal stockpile. Spontaneous combustion inhibitor should be sprayed effectively, considering the economic aspects, such as manufacturing cost etc.

Spontaneous Regression of a Large Lumbar Disc Extrusion

  • Ryu, Sung-Joo;Kim, In-Soo
    • Journal of Korean Neurosurgical Society
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    • v.48 no.3
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    • pp.285-287
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    • 2010
  • Although the spontaneous disappearance or decrease in size of a herniated disc is well known, that of a large extruded disc has rarely been reported. This paper reports a case of a spontaneous regression of a large lumbar disc extrusion. The disc regressed spontaneously with clinical improvement and was documented on a follow up MRI study 6 months later. The literature is reviewed and the possible mechanisms of spontaneous disc regression are discussed.

Theoretical Analysis of the Spontaneous Emission Spectrum of a Device using DFB structures (DFB 구조 소자의 자연 방출 스펙트럼에 관한 이론적 해석)

  • 김부균;최지연;정기석;조성찬;이봉영
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.32A no.3
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    • pp.45-57
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    • 1995
  • We derive analytic expressions for the spontaneous emission spectrum of a device using DFB structures including the effects of both facet reflections and the phase of a grating. In solution of coupled mode equations. Equations for the reations between the spontaneous emission spectrum and structure parameters of the device are derived to investigate the effect of structure parameters on the spontaneous emission spectrum and operating characteristics of possibility of evaluating the structure parameters of the device from its spontaneous emission spectrum.

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The Comparison of Prosodic Phrasing in Spontaneous Speech and Read Speech (자유 발화와 낭독 발화의 운율 경계 형성 비교)

  • Noh, Seok-Eun
    • Proceedings of the KSPS conference
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    • 2006.11a
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    • pp.19-23
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    • 2006
  • This paper is for the comparison of prosodic phrasing in Korean spontaneous speech and read speech. For this comparison, The subjects read the transcriptions from their own spontaneous speech. The number of IP in spontaneous speech is more than in read speech, while The number of AP has no difference between them. A accentual phrase in spontaneous speech has less syllable than read speech.

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Spontaneous Electrical Activity in Cerebellar Purkinje Neurons of Postnatal Rats

  • Nam, Sang-Chae
    • The Korean Journal of Physiology and Pharmacology
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    • v.1 no.4
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    • pp.355-366
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    • 1997
  • Although cerebellar Purkinje cells display spontaneous electrical activity in vivo and in slice experiments, the mechanism of the spontaneous activity generation has not been clearly understood. The aim of this study was to investigate whether cerebellar Purkinje cells of postnatal rats generate spontaneous electrical activity without synaptic inputs. Dissociated cerebellar Purkinje cells were used for reducing synaptic inputs in the present study. Cerebellar Purkinje cells with dendrites were dissociated from postnatal rats using enzymatic treatment followed by mechanical trituration. Spontaneous electrical activities were recorded from dissociated cells without any stimulus using whole-cell patch clamp configuration. Two types, spontaneously firing or quiescent, of dissociated Purkinje cells were observed in postnatal rats. Both types of cells were identified as Purkinje cells using immunocytochemical staining technique with anti-calbindin after recording. Spontaneously active cells displayed two patterns of firing, repetitive and burst firings. Two thirds of dissociated Purkinje cells displayed repetitive firing and the rest of them did burst firing under same recording condition. Repetitive firing activities were maintained even after further isolation using either physical or pharmacological techniques. Neither high magnessium solution nor excitatory synaptic blockers, AP-5 and DNQX, block the spontaneous activity. These results demonstrate that spontaneous electrical activity of isolated cerebellar Purkinje cells in postnatal rats is generated by intrinsic membrane properties rather than synaptic inputs.

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A comparison of phonological error patterns in the single word and spontaneous speech of children with speech sound disorders (말소리장애 아동의 단어와 자발화 문맥의 음운오류패턴 비교)

  • Park, kayeon;Kim, Soo-Jin
    • Phonetics and Speech Sciences
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    • v.7 no.3
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    • pp.165-173
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    • 2015
  • This study was aim to compare the phonological error patterns and PCC(Percentage of Correct Consonants) derived from the single word and spontaneous speech contexts of the speech sound disorders with unknown origin(SSD). The present study suggest that the development phonological error patterns and non-developmental error patterns of the target children, in according to speech context. The subjects were 15 children with SSD up to the age of 5 from 3 years of age. This research use 37 words of APAC(Assessment of Phonology & Articulation for Children) in the single word context and 100 eojeol in the spontaneous speech context. There was no difference of PCC between the single word and the spontaneous speech contexts. Significantly different developmental phonological error patterns between the single word and the spontaneous speech contexts were syllable deletion, word-medial onset deletion, liquid deletion, gliding, affrication, fricative other error, tensing, regressive assimilation. Significantly different non-developmental phonological error patterns were backing, addtion of phoneme, aspirating. The study showed that there was no difference of PCC between elicited single word and spontaneous conversational context. And there were some different phonological error patterns derived from the two contexts of the speech sound disorders. The more important interventions target is the error patterns of the spontaneous speech contexts for the immediate generalization and rising overall intelligibility.

The Application of Auriculotherapy to the Treatment of Chronic Spontaneous Urticaria: A Systematic Review and Meta-analysis

  • Zhu, Libing;Kim, Yunjin;Yang, Zongbao
    • Journal of Acupuncture & Meridian Studies
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    • v.11 no.6
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    • pp.343-354
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    • 2018
  • Auriculotherapy has been extensively used for chronic spontaneous urticaria in China. However, the evidence of its effectiveness and safety for the treatment of chronic spontaneous urticaria is insufficient. Hence, we conducted this study to compare auriculotherapy or auriculotherapy joint treatment with Western medicine for the cure of chronic spontaneous urticaria. This meta-analysis of seven randomized controlled trials showed that auriculotherapy or auriculotherapy joint treatment was significantly superior to Western medicine in curing clinical signs and symptoms of chronic spontaneous urticaria [odds ration (OR), 2.61; 95% confidence interval (CI), 1.54-4.43; p = 0.0004) and also better in total effect rate (OR, 3.81; 95% CI, 2.07-7.01; p<0.0001). But, auriculotherapy or auriculotherapy joint treatment was similar to Western medicine in improving clinical signs and symptoms of chronic spontaneous urticaria (OR, 0.74; 95% CI, 0.35-1.56; p = 0.42). Auriculotherapy or auriculotherapy joint treatment was safer than Western medicine for curing chronic spontaneous urticaria (OR, 0.26; 95% CI, 0.09-0.80; p = 0.02). Auriculotherapy alone or auriculotherapy joint treatment appears to be more effective and safer than Western medicine that contains antihistamines in the treatment of chronic spontaneous urticaria. However, these findings should be interpreted with caution due to the unclear risk bias of methodological quality, and further studies with large-scale, better, and more rigorously designed protocol are necessary to prove these findings.

The Comparison of the Spontaneous Zona Pellucida Hardening and PMA-induced Zona Pellucida Hardening during in Vitro Culture of the Mouse Oocytes (생쥐 난자 배양시의 자발적 투명대 경화 현상과 PMA에 의한 투명대 경화 현상 비교)

  • Kang, Hye-Na;Bae, In-Ha;Kim, Hae-Kwon
    • Clinical and Experimental Reproductive Medicine
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    • v.21 no.1
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    • pp.99-110
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    • 1994
  • One consequence of fertilization in mammals is an increased resistance of the zona pellucida (ZP) to proteases and various chemical reagents. This phenomenon has been called 'zona pellucida hardening' (ZPH), and it is generally accepted that it is caused by the secretory products of cortical granules released by the egg at fertilization. ZP of mouse oocytes maturing in vitro in a chemically defined medium becomes progressively more resistant to solubilization by chymotrypsin ("Spontaneous" ZP hardening). In the present study, it was aimed to find the specificity of spontaneous ZPH in relation to its possible relevance to the cortical reaction and the physiological block to polyspermy. When a maturation inhibitors, cAMP analog(dbcAMP) and phosphodiesterase inhibitor (IBMX) was added to culture medium, it prevent spontaneous ZPH of mouse oocyte during in vitro culture. Thus spontaneous ZPH requires GVBD, since it is prevented by those agents, which inhibit GVBD in vitro. However, culture for 3 hours in the presence of PMA(lOng/ml), a protein kinase C activator, resulted in ZPH without GVBD, thus suggesting that ZPH may be regulated independently apart from the event of GVBD. Pretreatment of mouse oocyte with FBS result in partially inhibitory effect on subsequent spontaneous ZPH. Induction of GVBD in vivo had a inhibitory effect on the spontaneous ZPH, but subsequent spontaneous ZPH. Induction of GVBD in vivo had a inhinbitory effect on the spontaneous ZPII, but had no inhibitory effect on PMA-induced ZPH. Treatment with a microfilament formation blocker(cytochalasin-B) at 1${\mu}g$/ml concentration, resulted in the excellent inhibitory effect on spontaneous ZPH. However cytochalasin-B did not inhibit PMA-induced ZPH. Thus this suggesting that spontaneuse ZPH had a different mechanism from PMA-induced ZPH.

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