• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제26회 추계학술대회
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• pp.217-224
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• 1997

Static characteristics of hemispherical aerodynamic bearing is studied theoretically. In this paper nonlinear equation of second order considering compressibility and slip effect of air is calculated by Newton-Raphson method. Results indicate that axial load capacity has maximum value when the inclination angle of groove is about 30$\circ$, the ratio of groove clearance to ridge clearance is two. We also present the design method of hemispherical Aerodynamic bearing based on it's load capacity taking into account manufacturing and assembling viewpoint.

• Journal of Korean Dental Science
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• 제9권2호
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• pp.55-62
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• 2016

Purpose: Alveolar bone develops with tooth eruption and is absorbed following tooth extraction. Various ridge preservation techniques have sought to prevent ridge atrophy, with no superior technique evident. Collagen has a long history as a biocompatible material. Its usefulness and safety have been amply verified. The related compound, atelocollagen, is also safe and displays reduced antigenicity since telopeptides are not present. Materials and Methods: The current study evaluated whether the $Rapiderm^{(R)}$ atelocollagen plug (Dalim Tissen, Seoul, Korea) improves tissue healing of extraction sockets and assessed the sequential pattern of bone regeneration using histology and microcomputed tomography in six beagle dogs. To assess the change of extraction socket, hard tissues were examined 2, 4, 6, and 8 weeks after tooth extraction. Result: The experimental groups showed better bone fill with slow remodeling process compared to the control groups although there was no statistical difference between groups. Conclusion: The atelocollagen seems to have a tendency to slow bone remodeling in the early phase of healing period and maintain remodeling capacity until late phase of remodeling. Also, use of atelocollagen increased the bone-to-tissue ratio compared to healing of untreated extraction socket.

• Animal Systematics, Evolution and Diversity
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• 제28권2호
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• pp.71-83
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• 2012

In this study, a new species, $Dimorphostylis$ $breviplicata$ n. sp. is described and illustrated on the basis of specimens collected from the shallow Korean waters. This new species is similar to $Dimorphostylis$ $brevicaudata$ (Zimmer, 1903), $Dimorphostylis$ $acroplicata$ Harada, 1960 and $Dimorphostylis$ $valida$ Gam$\hat{o}$, 1962 in that the carapace has three pairs of oblique ridges on the surface. However, the new species is distinguished by the combination of the following features: the middle oblique ridge is short and not joined to the other oblique ridges; the transverse ridge is absent on the frontal lobe; the dorso-median process on the pereonite 5 is only barely visible; the male telson has no short stout seta on the both lateral margins; the length ratio of the first to remaining articles combined on the male uropod is 1 : 0.7. A key to the Korean $Dimorphostylis$ species is provided. Also, $Diastylis$ $alaskensis$ Calman, 1912 is redescribed as a new recorded species of the Korean fauna.

• 한국유기농업학회지
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• 제24권4호
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• pp.719-733
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• 2016

본 논문은 앞그루작물 재배 시 형성된 이랑을 재활용하여 다음 뒷그루작물을 무경운으로 재배할 경우 토양의 이화학성과 생육 및 수량에 미치는 영향을 구명하고자 추진한 연구 결과의 일부이다. 토양에서 경운 후 시간의 경과에 따른 토양 입자 크기의 분포를 조사한 결과 관행경운과 무경운 토양 입자는 공히 입상구조(granular structure)를 이루고 있었다. 무경운 토양의 입자 크기 2 mm 이상의 분포는 무경운 토양이 경운 토양에 비하여 표토와 심토 공히 증가 되었다. 그리고 내수성입단 0.25 mm 이상 0.5 mm 이하와 0.5 mm 이상 1 mm 이하, 1 mm 이상의 대입단 분포는 경운과 무경운 1년차 토양에서 유의적인 차이가 없었으나, 무경운 2년차에서는 입단의 크기별로 각각 8.2%, 4.5%, 1.7%로 경운과 무경운 1년차에 비하여 유의적인 증가를 보였다. 관행 경운 토양 표토의 용적밀도 $1.10MG\;m^3$이 무경운 1년차에서 $1.30MG\;m^3$으로 증가 되었으나, 무경운 2년차는 $1.14MG\;m^3$, 무경운 3년차는 $1.03MG\;m^3$으로 용적밀도가 감소되었으며, 심토도 같은 경향이었다. 따라서 용적밀도와 정(+)의 상관이 있는 고상율은 표토와 심토 공히 무경운 1년차에서 관행 경운 토양에 비하여 증가되었으나, 무경운 2년차와 3년차는 감소되었다. 용적밀도 및 고상율과 부(-)의 상관관계가 있는 공극율은 경운 토양 58.5%가 무경운 1년차는 51%로 8.5% 감소되었으나, 무경운 2년차는 56.9%, 무경운 3년차는 61.2%로 증가되었으며, 심토도 같은 경향이었다. 공극율과 정(+)의 상관관계가 있는 기상율은 관행경운 토양에 비하여 무경운 1년차는 감소되었으나, 무경운 2년차와 3년차에서는 증가되었다. 그리고 기상과 함께 공극율을 결정하는 액상율은 경운 표토 24.2%가 무경운 1년차는 28.3%로 증가되었으나, 무경운 2년차는 23.4%, 무경운 3년차는 18.3%로 현저하게 감소되었으며, 심토도 같은 경향이었으나, 심토의 액상율은 표토에 비하여 증가되었다.

• ALGAE
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• 제22권4호
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• pp.253-259
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• 2007

This study deals with the taxonomy of the marine diatom Ditylum brightwellii (West) Grunow: shape, size and ratio, marginal ridge, labiate process, areolation, and seasonal distribution are all considered. Ditylum brightwellii were divided into two type; prism- and cylinder-shaped. Comparisons between specimens from the Yellow Sea were made on, (1) shape- prism types are prismatic-shaped and/or regular square or right-angled tetragon, cylinder types are cylinder-shaped and/or long right-angled tetragon in the girdle view, respectively; (2) size and ratiodiameters of prism types are 82.1 ± 2 μm, while those of cylinder types are 21.2 ± 5 μm and ratio of pervalvar axis/diameter- prism types cells are 1.0-1.5, but cylinder types are 3.9-5.5; (3) marginal ridges- prism types have dotted, while those of the cylinder-type cells have piece, slotted or fimbriated on the marginal ridge; (4) labiate process- both prism- and cylinder-types are central part in valve face, but length of labiate processes of prism types are longer than those of cylinder types; (5) cell margin- the girdle margin show many shallow furrows in prism type and smooth in cylinder type; (6) areolation- both prism- and cylinder-types are a radial pattern in the valve center, but areolae of prism types are larger than those of cylinder types; (7) seasonal distribution- cylinder types are dominated in summer and prism types in the other seasons.

• 대한후두음성언어의학회지
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• 제11권1호
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• pp.76-80
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• 2000

Tongue-tip trill is a sound made by the tongue tip making contract with the alveolar ridge and oscillating rapidly as sound is produced. It is an exercise used by many singers to warm up the voice and used as one of the methods of voice rehabilitation for patients who have the vocal folds scarred postoperatively and also who present with a variety of disorders, particularly hypofunction and presbyphonia. We intended to investigate the mucosal vibration of the true vocal folds on tongue-tip trill by electroglottography and to find e effective methods of tongue-tip trill. One adult male volunteer participated. Spectrography and electroglottography were checked repeatedly 15 times, more than 5 second in each times, at same pitch, in three conditions of phonation : sustained /a/ vowel, anterior trill in which tongue-tip vibrated at anterior portion of alveolar ridge just behind the anterior tooth, and posterior trill in which at palatal crest behind the transverse palatine fold We measured the first and second formant to determine indirectly the position of tongue and calculated speed quotient and the ratio of closing phase to closed phase. Speed quotients of posterior trill were higher than sustained /a/ vowel and anterior trill in 14 times. The ratio of closing phase to dosed phase of posterior trill were lower than the others in 14 times. Mucosa of true vocal folds is vibrated more effectively on posterior trill rather than sustained /a/ vowel and anterior trill. So, when tongue-tip trill is used as a method of voice rehabilitation, we suggest that posterior trill is better in producing effective mucosal vibration

• 한국환경생태학회지
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• 제27권6호
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• pp.704-717
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• 2013

본 연구는 북한산국립공원을 대상으로 참나무시들음병 피해지에 대한 감염단계별 현황을 정밀조사하고 이를 지도화하여 감염피해 관리 및 예방을 위한 기초자료를 제공하고자 하였다. 유역권을 고려한 현존식생 polygon을 맵핑단위로 설정하여 참나무류 분포지역을 조사하였으며 관리지구별 감염피해율 및 감염 단계별 가중치를 적용하여 산정한 감염지수 현황을 맵핑하였다. 북한산국립공원 전체 참나무류 감염피해율은 58.5% 이었고, 경피해율 29.6%, 중피해율 16.1%, 심피해율 8.8%, 고사율 4.1% 등 이었다. 원도봉의 범골능선에서 정릉지구의 형제봉능선까지의 감염정도가 심하였고 북한산국립공원의 주능선을 중심으로 서측의 송추지구, 산성지구, 구기지구는 상대적으로 피해정도가 약하였으나 능선부와 주요 계곡부 상부 일대에서 감염피해율은 높았다. 감염지수는 피해 미약 지역이 전체 참나무류 면적의 39.1%, 가벼운 피해 지역이 41.0%, 중간 피해 지역이 전체 면적의 16.1%, 심각한 피해 지역이 전체 면적의 3.3%, 대부분 고사 위험 피해 지역이 전체 면적의 0.4%이었다. 심피해와 고사목이 다수 확인된 도봉지구의 무수골계곡과 자운봉 일대의 감염지수가 높았으며 정릉지구의 보현봉 일대와 산성지구의 효자리계곡 일부지역에서도 감염정도가 심각하였다. 북한산국립공원의 각 지구별 참나무류 분포면적 대비 예측 감염주수 산정 결과, 전체 참나무류 주수 2,709,147주 중 감염주수는 총 1,585,937주 이었다. 우이지구가 참나무류 352,931주 중 306,161주가 감염되어 피해가 가장 심하였고 피해가 가장 적은 구기지구는 참나무류 145,747주 중 53,141주가 감염되었다.

• 한국환경농학회지
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• 제35권3호
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• pp.202-210
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• 2016

BACKGROUND: This study was conducted to determine effects of ridging systems and plastic film mulch types on growth, yield, and profitability of potato (Solanum tuberosum L.) in spring cropping using paddy field and to suggest profitable ridging system and plastic mulch type.METHODS AND RESULTS: Two potato cultivars ('Goun', and 'Atlantic') were grown at paddy field located in Gangneung in spring. For treatments, ridging systems were one-row ridge (OR) and two-row ridge (TR). Mulch types were no-mulch (NM), black plastic film mulch (BPM), and transparent plastic film mulch (TPM). Emergence of sprout was affected by the mulch types and the fastest level was shown at TPM treatment. Accumulative soil temperature during sprouting was 16.2℃ higher at TR than at OR and also higher at TPM than at BPM or NM. Stem length was not affected by ridging systems or mulch types. Leaf area index (LAI) was influenced by mulch types, while not by ridging systems. The highest LAI was shown at TR with TPM and OR of BPM. There was no significant difference in specific gravity or dry matter rate by ridging systems and mulch types. Tuber yield was significantly influenced by ridging systems and mulch types. Mean tuber weight was heavier at OR treatment than at TR and also the heaviest at TPM among mulch types. The highest marketable yield was found at OR with BPM. Based on marketable tuber yield and market price, the highest income ratio in two cultivars was found at OR with BPM and it was 20~82% higher than the ratio at TR with TPM.CONCLUSION: In spring potato cropping using paddy field, OR with BPM is better for high yield and is more profitable for farmer's income than the conventional cultivation method, TR with TPM.

• Journal of Advanced Marine Engineering and Technology
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• 제26권6호
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• pp.646-652
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• 2002

The influence of reciprocating frequency and radius on heat transfer in the roughened rectangular channel is experimentally investigated. The aspect ratio (width/height) of the duct is 2.33 and the rib height is one fifteenth of the duct height. And the ratio of rib-to-rib distance to rib height is 10. The discrete ribs were periodically attached to the button wall of the duct with a parallel orientation. The parametric test matrix involves Reynolds number, reciprocating, and reciprocating radius, in the ranges, 1,000∼6,000, 1.7∼2.5 HB and 7∼15cm, respectively. The combined effects of reciprocating frequency and reciprocating radius have considerable influence on the heat transfer due to the modified vortex flow structure.

• 대한환경공학회지
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• 제38권5호
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• pp.228-235
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• 2016

아질산화 반응을 통한 nitrite 축적은 단축질소제거 혹은 anammox 공정 수립을 위해 필수적이고 이 반응의 속도가 전체 질소제거공정의 효율에 큰 영향을 미칠 수 있다. 본 연구는 부유 미생물 연속류 반응기에서 pH 농도가 암모니아 폐수(2,000 mgN/L) 처리에 주는 복잡하고 다양한 영향 들을 modeling과 실험을 통해 종합적으로 분석하였다. modeling 연구 결과 반응의 안정성(stability)은 pH에 의해 지대한 영향을 받으며, free ammonia 저해가 심해지는 알칼리성 환경일수록 안정적 운전 영역(stable region)은 축소되었다. 기질과 pH의 좌표 상에서 stable region과 unstable region을 가르는 경계(stability ridge) 근처에서 안정적인 최대반응속도를 얻을 수 있고, 이 운전조건에서 아질산 축적 가능성도 최대가 되었다. stability ridge 근처의 조건에서 반응기를 운전한 결과 아질산화속도는 안정적으로 약 $6kgN/m^3-d$까지 얻을 수 있었고, 아질산축적율은 약 99% 이었다. 그러나 unstable region에서는 부하증가를 통한 반복된 교란 결과 유출수 암모니아 농도가 회복 불가능한 상태로 상승하였다. Modeling 결과 고유(intrinsic) 최적 pH 값을 고정하여도 실험에서 관찰되는 최적 운전 pH는 사용 기질의 농도가 높을수록 낮아지는 것으로 나타났으며, 이는 문헌에서 보고된 경향과 일치 하였다. 본 연구의 modeling 조건에서 95% 아질산화(5%는 암모니아로 잔존)를 위한 최적 운전 pH는 ~8.0인 것으로 예측되었으나, anammox 유입수 생산을 위해 55% 아질산화하려 할 때의 최적 운전 pH는 ~7.2로 낮아 졌다.