• 한국유체기계학회 논문집
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• 제9권1호
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• pp.25-31
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• 2006

The present study investigates the effects of bleed flow on heat/mass transfer and pressure drop in a rotating channel with transverse rib turbulators. The hydraulic diameter $(D_h)$ of the square channel is 40.0mm. The bleed holes are located between the rib turbulators on leading surface and the hole diameter (d) is 4.5 mm. The square rib turbulators are installed on both leading and trailing surfaces. The rib-to-rib pitch is 10.0 times of the rib height(e) and the rib height-to-hydraulic diameter ratio $(e/D_h)$ is 0.055. The tests were conducted at various rotation numbers (0, 0.2, 0.4), while the Reynolds number and the rate of bleed flow to main flow (BR) were fixed at 10,000 and $10\%$, respectively. The results suggest that the heat/mass transfer characteristics in the internal cooling passage are influenced by rib turbulators, bleed flow and the Coriolis force induced by rotation. For the rotating ribbed passage with bleed flow, the heat/mass transfer on the leading surface is hardly affected by bleed flow, but that on the trailing surface decreases due to the diminution of main flow. The results also show that the friction factor decreases with the bleed flow.

• Spatial Information Research
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• 제16권2호
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• pp.193-206
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• 2008

스테레오 영상으로부터 수치표고모델을 생성하기 위해서는 일반적으로 두 영상 간의 정합을 수행한다. 정합은 초기 정합 후보점으로부터 시작되며, 두 영상 간의 접합점(Tie-points)이 이러한 초기 후보점 역할을 하게 된다. 이 초기 정합 후보점의 개수와 영상 내에서의 분포는 정합결과에 영향을 준다. 정합결과를 바탕으로 생성되는 수치표고모델에는 에러가 포함된다. 이러한 에러를 제거하는 가장 보편적인 방법은 주변값으로 보간하는 것이다. 본 논문에서는 신뢰성 있는 수치표고모델을 자동으로 생성하기 위해서 기존 수치표고모델을 이용하여 자동으로 추출한 접합점(Tie-points)과 영상 피라미드 그리고 정합 결과에서 발생한 이상값(Outlier)을 기존 수치표고모델로 보정하는 방법을 제안한다. 본 논문에서는 IKONOS, QuickBird, SPOTS 스테레오 영상과 DTED level 2 데이터를 이용하여 실험을 수행했으며, 실험결과를 통해서 제안된 방법으로 생성한 수치표고모델에서는 에러가 모두 제거되었음을 보여준다. 또한 기존 DTED level 2를 참값으로 하여 산출된 높이값에 대한 RMSE는 15m 미만으로, 비교적 정확한 수치표고모델을 생성하였음을 보여준다.

• 한국농공학회지
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• 제24권2호
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• pp.49-55
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• 1982

The purpose of this study is to classify the factors influenced on the damages of head works suffered from the storm flood occurred on July 22 1980 in both Musim and Bochong rivers and to find out an integral counter measures against the causes influenced on the disaster of head works in the engineering aspect of planning, design, construction and maintenance. In this survey, number of samples was taken 25 head Works, and the counter measures against the causes of their disasters summarized was as follows, 1. In the aspect of planning a. As the flood water level after the establishment of head works is more increased than the level before setting of head works owing to having more gentle slope of river bed between the head works than nature slope of river bed. Number of head works should be reduced for the appropriate annexation of them b. In the place where head works is established on the curved point of levee, the destruction of levee becomes severe by the strong deflective current. Therefore the setting of head works on the curved point should be kept off as long as possible and in case of unavoidable circumstances the construction method such as reinforced concrete wall or stone wall filed with concrete and anchored bank revetments should be considered. 2. In the aspect of design a. As scoring phenomena at up stream is serious around the weir Where the concentration of strong current is present in such a place, up stream apron having impermeability should be designed to resist and prevent scoring. b. As the length of apron and protected bed is too short to prevent scoring as down stream bed, the design length should be taken somewhat more than the calculated value, but in the case the calculated length becomes too long to be profitable, a device of water cushion should be considered. c. The structure of protected river bed should be improved to make stone mesh bags fixed to apron and to have vinyl mattress laid on river bed together with the improvement for increasing the stability of stone mesh bags and preventing the sucked sand from the river bed. d. As the shortage of cut-off length, especialy in case of the cutoffs conneting both shore sides of river makes the cause of destruction of embankment and weir body, the culculation of cut-off length should be taken enough length based on seepage length. 3. In the aspect of design and constructions a. The overturing destruction of weir by piping action was based on the jet water through cracks at the construction and expansion joints. therefore the expansion joint should be designed and constructed with the insertion of water proof plate and asphalt filling, and the construction joint, with concaved shape structure and steel reinforcement. b. As the wrong design and construction of the weep holes on apron will cause water piping and weir destruction, the design and construction of filter based on the rule of filter should be kept for weep holes. c. The wrong design and construction of bank revetment caused the severe destruction of levee and weir body resulting from scoring and impulse by strong current and formation of water route behind the revetment. Therefore bank revetment should be designod and constructed with stone wall filled with concrete and anchored, or reinforced concrete wall to prevent the formation of water flow route behind the wall and to resist against the scoring and impulse of strong stream. 4. In the aspect of maintenance When the damaged parts occurred at head works the authorities and farmers concerned should find and mend them as soon as possible with mutual cooperation, and on the other hand public citizen should be guided for good use of public property.

• 한국작물학회지
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• 제54권3호
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• pp.294-298
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• 2009

감자 분무경산 소괴경을 심지양액 재배하여 기본식물을 생산할 때, 심지의 배치방법에 따른 씨감자의 생산성 조사하고, 심지를 수평으로 배치할 때 알맞은 심지수를 구명하고자 상자($51{\times}31{\times}20cm$, $0.16m^2$)당 심지 6개를 수직으로 배치하는 처리와 $2{\sim}10$개의 심지를 수평으로 배치하는 처리를 두었다. 괴경수는 심지 6개를 수직으로 배치하는 것에 비하여 수평으로 배치함으로 증가하였고 평균괴경중은 감소되어, 괴경수량은 심지 6개의 배치방법에 의하여 영향을 받지 않았다. 상위급씨감자로 사용될 수 있는 5 g 이상의 괴경수는 심지수가 2개에서 6개로 증가됨에 따라 2.8개/주에서 8.0개/주로 증가되었으나, 심지수 6 이상에서는 더 증가되지 않았다. 평균괴경중은 심지수 8개까지 심지수가 많을수록 무거웠으나 심지수 10개에서는 더 이상 무거워지지 않았다. 5 g 이상의 괴경수량은 심지수가 2개에서 6개로 증가됨에 따라 1.81 kg/$m^2$에서 9.72 kg/$m^2$으로 크게 증가되었다가, 8개 이상에서는 심지수 증가에 따라 완만히 증가되어 심지 10개 처리구에서는 12.9 kg/$m^2$이었다. 씨감자 수량과 심지비용, 배지충진 작업의 편리성을 고려할 때 상자당 심지 8개(50.6개/$m^2$)를 상자의 밑면에 눕혀 수평으로 배치하는 것이 유리할 것으로 판단된다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7121-7126
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• 2013

Aim: To examine lymph nodes obtained after lipolysis and liposuction of subcutaneous fat of the inguinal region of female vulvar cancer patients to explore the feasibility of clinical application. Methods: The field of operation was on the basis of the range of the conventional resection of inguinal lymph nodes. We injected lipolysis liquid fanwise, started liposuction after 15-20 minutes; then the subcutaneous fatty tissue was sucked out clearly by suction tube. We selected the first puncture holes located on 2-3 cm part below anterior superior spine, the others respectively being located 3cm and 6cm below the first for puncturing into the skin, imbedding a trocar to intorduce $CO_2$ gas and the specular body, and excise the lymph nodes by ultrasonic scalpel. The surgical field chamber was set with negative pressure drainage and was pressured with a soft saline bag after surgery. Results: A lacuna emerged from subcutaneous of the inguinal region after lipolysis and liposuction, with a wide fascia easily exposed at the bottom where lymph nodes could be readily excised. The number of lymph nodes of ten patients excised within the inguinal region on each side was 4-18. The excised average number of lymph nodes was 11 when we had mature technology. Conclusion: Most of adipose tissue was removed after lipolysis and liposuction of subcutaneous tissue of inguinal region, so that the included lymph nodes were exposed and easy to excise by endoscope. This surgery avoided the large incision of regular surgery of inguinal region, the results indicating that this approach is feasible and safe for used as an alternative technology.

• Journal of Communications and Networks
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• 제16권2호
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• pp.227-237
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• 2014

Throughput scaling laws for two coexisting ad hoc networks with m primary users (PUs) and n secondary users (SUs) randomly distributed in an unit area have been widely studied. Early work showed that the secondary network performs as well as stand-alone networks, namely, the per-node throughput of the secondary networks is ${\Theta}(1/\sqrt{n{\log}n})$. In this paper, we show that by exploiting directional spectrum opportunities in secondary network, the throughput of secondary network can be improved. If the beamwidth of secondary transmitter (TX)'s main lobe is ${\delta}=o(1/{\log}n)$, SUs can achieve a per-node throughput of ${\Theta}(1/\sqrt{n{\log}n})$ for directional transmission and omni reception (DTOR), which is ${\Theta}({\log}n)$ times higher than the throughput with-out directional transmission. On the contrary, if ${\delta}={\omega}(1/{\log}n)$, the throughput gain of SUs is $2{\pi}/{\delta}$ for DTOR compared with the throughput without directional antennas. Similarly, we have derived the throughput for other cases of directional transmission. The connectivity is another critical metric to evaluate the performance of random ad hoc networks. The relation between the number of SUs n and the number of PUs m is assumed to be $n=m^{\beta}$. We show that with the HDP-VDP routing scheme, which is widely employed in the analysis of throughput scaling laws of ad hoc networks, the connectivity of a single SU can be guaranteed when ${\beta}$ > 1, and the connectivity of a single secondary path can be guaranteed when ${\beta}$ > 2. While circumventing routing can improve the connectivity of cognitive radio ad hoc network, we verify that the connectivity of a single SU as well as a single secondary path can be guaranteed when ${\beta}$ > 1. Thus, to achieve the connectivity of secondary networks, the density of SUs should be (asymptotically) bigger than that of PUs.

• 한국해양학회지:바다
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• 제28권4호
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• pp.143-157
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• 2023

본 연구는 바지락과 쏙의 서식 구역이 대비되는 보령 주교 갯벌의 인위적인 환경 영향에 의한 저서동물 군집 특성을 확인하였다. 조사 기간 내 대형저서동물은 총 55종이 출현하였으며, 평균 서식밀도는 338 ind./m², 생체량은 212.2 gWWt/m²이었다. 출현 종수는 상부(27종)에서 하부(37종)로 갈수록 증가하였고, 우점종은(상부: 둥근가시사자머리참갯지렁이, 중부: 고리버들갯지렁이, 하부: 바지락) 조위별로 다르게 나타났다. 집괴분석과 다차원척도법을 이용한 상위 10종의 저서동물 군집구조는 하부의 바지락 어장과 쏙 서식공 밀도가 높은 중부 정점 중심의 두 그룹으로 나뉘며, 특정 생물 종의 영향을 반영하였다. 쏙 서식 공간의 퇴적물 입도 조성은 변동 폭이 컸으나 연간 유지되었으며, 분급은 2.1 𝜑로 낮아져 같은 입자로 구성된 비율이 증가하였다. 특히, 중부는 인위적인 영향이 높음에도 고리버들갯지렁이가 우점하고, 쏙 서식공 밀도와의 연관성을 보여 이는 종간 상호작용에 기인하는 것으로 판단된다.

• Clinical and Experimental Reproductive Medicine
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• 제26권2호
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• pp.185-192
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• 1999

The present study was performed to investigate the efficacy and safety of laser assisted hatching (AH) on mouse embryos. Non-contact $1.48{\mu}m$ diode laser system used to create a precise hole on zona pellucida. 2-cell embryos were collected from the mice (ICR) that had the coitus vaginal plug confirmed at 48 hours after hCG injection. Collected 2-cell embryos were cultured in the HTF medium supplemented with 0.4% BSA. For experiments, embryos at 8-cell stage were used after 18-22 hours in culture. After assisted hatching, the embryos were further cultured in HTF medium containing 0.1% PVP (anti-hatching system) for 3 days. For evaluate efficiency of laser on mouse embryo hatching, the effect of AH methods (acidic tyrode, pronase and laser), the number of artificial holes (1, 2 and 3 hole) and the irradiation time of laser (2, 4, 6, 8 and 10 ms) were examined. Hatching rates of laser AH group (95.2%) was significantly higher than that of control group (50.8%), but there was no differences among the laser (95.2%), acidic tyrode (100%) and pronase (98.5%) groups. Hatching rates of the number of zona pellucida opening by laser, there were no differences among the 1 hole (87.5%),2 hole (92.1%) and 3 hole (85.9%) groups. Developmental and hatching rates of embryos according to laser irradiation time were similar in the treatment groups. Therefore, these results suggest that laser AH using non-contact $1.48{\mu}m$ diode laser is a simple and accurate and effective procedure for AH. Based on these results, laser AH could be use safely for human ART program.

• Journal of the Korean Wood Science and Technology
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• 제38권4호
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• pp.306-315
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• 2010

상대적으로 단면이 작은 부재를 현장에서 조립하는 응력적층 방식은 방부처리 및 운반, 설치 등에 장점을 가지고 있어 경간이 짧고 통행빈도가 낮으면서 현장접근이 불리한 휴양림 진입로나 임도 등의 목조교량에 활용 가능성이 높다. 따라서 본 논문에서는 응력적층재를 이용한 차량용 교량의 구조설계기술 개발의 일환으로 방부 처리된 국산 리기다소나무로 제작된 응력적층재의 거동 특성을 실험실적으로 분석하였다. 먼저 방부처리에 의한 리기다소나무의 횡압축 성능 변화와 응력적층재 제작과정에서 요구되는 중앙천공이 제재목의 휨성능에 미치는 영향을 분석하였다. 다음으로 응력적층재의 설계시에 고려되어야 할 것으로 판단되는 프리스트레스 압체력, 볼트간격, 층재개수, 평삭가공 여부가 휨성능에 미치는 영향을 확인하였다. 연구결과 응력적층재 제작과정에서 제재목의 평삭가공은 불필요하며, 3.0 kg/$cm^2$ 이상의 프리스트레스 압체력에서 부재의 휨강성이 기준의 80% 수준으로 유지됨이 확인되었다. 볼트간격과 층재개수의 영향에 대해서는 추후 현장실험 등을 통해 보다 넓은 범위에서의 검토가 요구된다. 본 연구결과는 국내 차량용 목조교량을 도입하기 위한 구조해석 및 설계절차를 확립하는데 있어서 기초자료로 활용될 것으로 기대된다.

• 한국산림과학회지
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• 제70권1호
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• pp.38-44
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• 1985

국립공원(國立公園) 지리산(智異山) 야서(野鼠)의 피해방제(被害防除)에 대(對)한 기초적(基礎的)인 자료(資料)에 기여(寄與)할 목적(目的)으로 1983년(年) 10월(月)부터 '84년(年) 9월(月)까지 장당(壯堂)과 유평(油坪), 중산리(中山里), 세석(細石), 대성지역(大成地域)의 5개지역(個地域)을 중심(中心)으로 야서(野鼠)의 서식실태(棲息實態)를 조사(調査)하여 보았던바 다음과 같은 결과(結果)를 얻었다. 1) 발견(發見)된 서류(鼠類)는 대륙밭쥐(Clethrionomys rufocanus regulus)와 흰넓적다리 붉은쥐(Apodemus speciosus peninsulae), 등줄쥐(Apodemus agrarius coreae) 등(等)의 3종(種)이었다. 2) 소혈(巢穴)의 유형(類型)은 3종(種)의 서류(鼠類) 모두다 근원(根元)과 도목하(倒木下), 암석(岩石)과 지면(地面)의 경계(境界), 경사지표면(傾斜地表面), 지표면(地表面) 등(等)을 이용(利用)하는 5개(個) 유형(類型)이 있었으며 그중(中)에서도 수목(樹木)의 근원부위(根元部位)를 이용(利用)하는 것이 33.2%로서 가장 많았다. 3) 서식율(棲息率)은 대성지역(大成地域)이 22.6%로서 가장 많았으며 월별(月別)로 보면 7월(月)이 가장 많이 포획되었다. 4) ♀, ♂ 별(別)로 보면 ♀은 세석지역(細石地域)에서는 7월(月)이 6.6%로서 가장 많이 서식(棲息)하였으며 ♂은 유평지역(油坪地域)에서는 7월(月), 세석지역(細石地域)에서는 5월(月), 대성지역(大成地域)에서는 7월(月)에 각각(各各) 5.4%로서 가장 많이 서식(棲息)하였다. 5) 체중(體重)을 보면 최하(最下) 20.3g에서 57.4g였었는데 그중(中) 대륙밭쥐(Clethrionomys rufocanus regulus)가 37.8g으로 가장 무거웠고 그 다음이 흰넓적다리붉은쥐(Apodemus specious peninsulae), 등줄쥐 (Apodemus agrarius coreae)의 순(順)이었고 지역별(地域別)로 보면 대성지역(大成地域)이 가장 무거웠다.