• Title/Summary/Keyword: Mouth wind

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Geomorphological Properties and Changes on River-Mouth Bar at Song-cheon River (송천 하구 사주의 지형 특성과 변화 과정)

  • Lee, Gwang-Ryul
    • Journal of the Korean Geographical Society
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    • v.46 no.6
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    • pp.693-706
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    • 2011
  • The Geomorphological properties and ages of river-mouth bar at Song-cheon River in the East Coast of Korea, Yeongdeok-gun, Gyeongbuk Province are estimated, and the long-term and short-term changing processes and causes are analyzed. Sand grains of the bar near the coastline show the finer trends from south to north and these can be attributed to the northward movement of waves and long-shore currents. The absolute ages of bar and nearby coastal sand dune are less than approximately 100 years ago, indicating that the bar has experienced the active geomorphological changes. While the inlet located at south part of the bar between 1971 and 1995, the inlet has located at north or middle part since 1995. These may caused by the changes of movement directions of waves and long-shore currents due to the apparent northward movements of winds and currents. In short-term, the higher elevation, larger area, simpler landform relief and more variable location of inlet and morphology of bar can be observed between September and March due to the dominance of sedimentary processes by wave and wind processes.

Reduction of Soot Emitted from a $C_2$$H_4$ Normal Diffusion Flame with Application of DC Corona Discharge (DC 코로나 방전이 적용된 에틸렌 정상 확산 화염의 Soot 배출 저감)

  • Lee, Jae-Bok;Hwang, Jeong-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.4
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    • pp.496-506
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    • 2001
  • The effect of corona discharge on soot emission was experimentally investigated. Size and number concentrations of soot aggregates were measured and compared for various voltages. Regardless of the polarity of the applied voltage, the flame length decreased and the tip of flame spreaded with increasing voltage. For the experimental conditions selected, the flame was blown off toward the ground electrode by corona ionic wind. When the negative applied voltage was greater than 3kV(for electrode spacing = 3.5cm), soot particles in inception or growth region were affected by the corona discharge, resulting in the reduction of number concentration. The results show that the ionic wind favored soot oxidation and increased flame temperature. Number concentration and primary particle size greatly increased, when the corona electrodes were located the region of soot nucleation or growth(close to burner mouth).

On the Seasonal Variation of Urban Heat Island Intensity According to Meteorological Condition in Daegu (대구지역의 기상조건에 따른 도시열섬강도의 계절별 변화특성)

  • Ahn Ji-Suk;Kim Hae-Dong
    • Journal of Environmental Science International
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    • v.15 no.6
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    • pp.527-532
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    • 2006
  • The purpose of this study is to clarify the characteristic of urban heat island intensity in urban area formed at a basin. Thermal environments for basin-type cities are influenced by significant topographic relief winds. In this study, we analyzed the diurnal variations of the heat island intensity according to meteorological condition and season using AWS(Automatic Weather observation System) data in Daegu Metropolitan area for 1 year(3/April, 2003 $\sim$ 2/April, 2004). In this study, we defined the urban heat island intensity as the air temperature difference between two points, the downtown and the suburban area. The suburban area is located at valley mouth around the western tip of Daegu. The results are summarized as follows; 1. The maximum heat island intensity was recorded at early morning under the meteorological conditions, calm and clear 2. The heat island intensity was strong in the order of winter, fall, spring and summer. 3. The heat island intensity came out minus values in the afternoon. This phenomenon is known as a com mon for basin-type cities. 4. The heat island intensity was twice or more in clear and calm than not so.

A Study on the Connection of Layout and BIBO Landscape of Agricultural Villages in Gangwon Youngseo Province (강원 영서지역 농촌마을의 입지와 비보(裨補)경관과의 관계)

  • You, Jong-Duk;Yoon, Young-Hwal;Choi, Jang-Soon
    • Journal of the Korean Institute of Rural Architecture
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    • v.11 no.1
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    • pp.9-16
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    • 2009
  • This research surveyed the native resources which BiBo(replenishing shortages by helping each other) landscapes have been preserved by aiming at the village settlement spaces of five cities and counties in Gangwon Youngseo province. This research reveals that BiBo landscape patterns of 41 village forests, 23 BiBo symbols, and 6 BiBo ponds were surveyed. The village forests are all 41 places, and were mainly made on the plains in front of villages. BiBo functions of the forests were in the order of the land obstructing the view of the mouth of a river which is the most as 13 places, the land obstructing the view of the mouth of river, situation complements, village protection, and protection against wind. Bibo symbols were all 23 places. Towers, stone towers, menhirs, and Maitreya stones were 12 places, Jangseungs(a signpost raising on the entrance of the village or a temple) were 6 places, Sotdae(a pole raising at the entrance of the village as the symbol of a board or a village protecting deity) was 1 place, and the others were made multiply in 4 places. Bibo symbols were located at 21 places in front of villages. The village protection in Bibo functions was 6 places. 6 Bibo ponds were surveyed. Most Bibo ponds were made for earth power leakage prevention.

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전간(癲癎)에 대(對)한 문헌적(文獻的) 고찰(考察) (고전(古典)을 중심(中心)으로)

  • Lee, Il-Rang;Kim, Yeong-Man
    • The Journal of Korean Medicine
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    • v.1 no.1
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    • pp.63-73
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    • 1980
  • Through the classical records of the oriental medicine my investigation of the authorities of the epilepsy by classifying the etiology, symptoms and the treatments of it and camparing them has led to the following conclusion. 1) The etiology of 'epilepsy' can be classified into wind(風), sputum(痰), fever(熱) convulsion and caul. 2) The symptoms of it fall into the following nine ones; Sudden strong contraction making Sounds within the mouth, unoonsciousness, mutual jerks of the facial muscules foaming form the mouth, trismus contractive of extremities general body rigidity recovering after the fit and no rest. 3) The symptoms of Epilepsy are classified into 'Um type epilepsy'(癲) and the 'yang type epilepsy'(癎), and then the former has nine kinds in sympatomatic state and latter seventeen. 4) The treatment of the case can be made by using of cold drugs mainly for the purpose of mind purification(淸心), fever abatement(降火), Sputum-elimination(化痰) and normalization of metabolism(順氣) and Sometimes the function of the liver should be normalized by giving liver function normalizing medicine after Emetics. In comparison with the western way of using Anti convelsents therapy and electricshock therapy, the way of its treatment based on the classification of the causes is considered to be far more desirable.

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Characteristics of fishing condition variation of anchovy in the set net fishing ground of Anggang bay, korea (앵강만 정치망 어장의 멸치 어황변동 특성)

  • Lee, Gyu-Hyong
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.48 no.1
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    • pp.59-71
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    • 2012
  • In order to elucidate the mechanism of fishing condition variation of anchovy in the set net fisheries of Anggang Bay, the monthly catch of anchovy was analyzed and examined based on the data acquired from 2006 to 2010 in 13 different fishing grounds. Anchovy consistently appeared from April to December and reached the production of 840 to 1,424 t (average : 1,228 t), with a big annual variation. However, anchovy production in this area accounts for approximately 75% of the production by set net in Anggang Bay whereas it holds 6.8% of the nationwide production (=18,034 t) by set net. The school of anchovy starts to appear in April at the west mouth of the bay and move north-eastward. Afterward, having three of clockwise turns in the middle of the bay, they scatter to swim into the deep place of the bay and finally go out to turn back to their coming way. These behaviors of anchovy are likely related to thermal fronts as well as distributions of food. The production of anchovy (y, kg) relied greatly on frequencies of effective northeasterly ($x_1$) or northwesterly ($x_2$) wind (${\leq}$3.5m/s) which blow between April and June. Their relationships are as follows: $y=1086.27+21.499x_1-15.16x_2$ (r=0.901). Consequently, we concluded that the northeasterly wind, which appears in the breeding season of spring, played a role to retard the movement of anchovy school to the eastern sea, while the northwesterly wind inhibits the invasion of anchovy school into the bay.

Performance and Flow Characteristics of Axial Fan (축류팬의 성능 평가 및 주변 유동 특성)

  • 김재원;정윤영
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.11
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    • pp.972-981
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    • 2000
  • Comprehensive work is done for flows by an axial fan by experimental research. The present model fan is used for air handling device for out-door unit of an air conditioner in home appliance. PIV(Particle Image Velocimetry) system and wind tunnel are adopted for measurements of flows and performance evaluation, respectively. Major experimental conditions are the installation depth of a fan into a bellmouth of it. Optimal position of a fan in an inlet guide tube is observed by examination of fan-performance and flows in both upstream and downstream of the fan. Consequently, in the case of the fan inserted in half depth into the inlet tube, the efficiency of fan shows its maximum value and flow patterns is also streamlined.

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The microphone system of the cellular phone for privately telephonic communication (속삭임 통화를 위한 휴대 전화용 마이크로폰 시스템)

  • 최성준;문원규;이정현
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1335-1340
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    • 2001
  • The information technology brought us many kinds of conveniences to our life, but it also caused social problems such as privacy interference, unexpected personal information leaks, and nose generation by telephonic talks, etc. In this paper, the microphone system of the cellular phone is developed to prevent these problems caused by progress of information technology. The developed system was designed to detect only acoustic signals from a human being in the presence of various kinds of background noises. A windscreen was designed by use of micro-channels to eliminate the popping noise by the wind from the mouth of a speaker and four microphone array and signal processing techniques are applied to reduce background noise. The impact of the developed system was evaluated by experimental tests. The results show that the system can improve the required functions considerably.

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Treatment of Vertigo in Hyungsang Medicine (현훈(眩暈)의 형상의학적(形象醫學的) 치료(治療))

  • Kang, Kyung-Hwa;Kang, Duk-Soo;Lee, Yong-Tae
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.20 no.4
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    • pp.793-798
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    • 2006
  • Vertigo is one of the subjective symptoms which appears commonly in so many diseases that it is often neglected. But it needs active medical care because it can be a forewarning of serious illness like cerebral apoplexy. This thesis makes a study of vertigo in view of Hyungsang medicine. The followings are the conclusion drawn in diagnosis and treatment of Vertigo: Excess in the upper and deficiency in the lower part(上實下虛) is a main cause of male vertigo. Deficiency in the upper and excess in the lower part(下虛上實) is a general cause of female vertigo. Vertigo is also caused by the insufficiency of the kidney water(腎水) or reservoir of marrow(髓海). persons of Jung pe(精科) with large check bones , those of Fish type(魚類) with Dig mouth and thick lips ; and those with large heads are mainly attacked by this cause. A fleshy person's vertigo comes from the deficiency of Ki and damp phlegm(氣虛濕症) so it is cured by reinforcing Ki, removing dampness and dispelling phlegm. A slim person's vertigo comes from the deficiency of blood and dryness heat(血虛有火) so it is treated by tonifying the blood, cleaning heat away the heat. In case of womanly shaped male and manly shaped female, the vertigo is due to the phlegm fire. Wind-heat(風熱) can cause vertigo generally 施 the persons of following types : wind type(風人), running animal type(走類),bird type(烏類), and Yangmyung meridian type (陽明形). Vertigo also comes from consumption. The deficiency of Ki can be a cause of vertigo in case of male; persons with pale complexion; and those with pronounced noses. The deficiency of blood can be a reason of vertigo in the persons of Hyul type(血科) and those with pale eyelids and lips. The hypofunction of the splean and stomach brings on the deficiency of Ki and blood, which can give rise to the vertigo for those with large nose and mouth. The old people's vertigo comes from the hypofunction of Ki, blood, Yin and Yang.

Effect of impingement edge geometry on the acoustic resonance excitation and Strouhal numbers in a ducted shallow cavity

  • Omer, Ahmed;Mohany, Atef;Hassan, Marwan
    • Wind and Structures
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    • v.23 no.2
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    • pp.91-107
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    • 2016
  • Flow-excited acoustic resonance in ducted cavities can produce high levels of acoustic pressure that may lead to severe damage. This occurs when the flow instability over the cavity mouth, which is created by the free shear layer separation at the upstream edge, is coupled with one of the acoustic modes in the accommodating enclosure. Acoustic resonance can cause high amplitude fluctuating acoustic loads in and near the cavity. Such acoustic loads could cause damage in sensitive applications such as aircraft weapon bays. Therefore, the suppression and mitigation of these resonances are very important. Much of the work done in the past focused on the fluid-dynamic oscillation mechanism or suppressing the resonance by altering the edge condition at the shear layer separation. However, the effect of the downstream edge has received much less attention. This paper considers the effect of the impingement edge geometry on the acoustic resonance excitation and Strouhal number values of the flow instabilities in a ducted shallow cavity with an aspect ratio of 1.0. Several edges, including chamfered edges with different angles and round edges with different radii, were investigated. In addition, some downstream edges that have never been studied before, such as saw-tooth edges, spanwise cylinders, higher and lower steps, and straight and delta spoilers, are investigated. The experiments are conducted in an open-loop wind tunnel that can generate flows with a Mach number up to 0.45. The study shows that when some edge geometries, such as lower steps, chamfered, round, and saw-tooth edges, are installed downstream, they demonstrate a promising reduction in the acoustic resonance. On the other hand, higher steps and straight spoilers resulted in intensifying the acoustic resonance. In addition, the effect of edge geometry on the Strouhal number is presented.