• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
• /
• pp.282-284
• /
• 1996

This paper presents prebreakdown characteristics of $SF_6$ gas stressed by the non-oscillating and oscillating impulse voltages in inhomogeneous fields disturbed by metallic protrusion. The purpose of this investigation is to present the predischarge development and dielectric characteristics of $SF_6$ gas under VFTOs. The experiments were carried out using a needle-to-plane gap geometries in the gas pressure ranges from 0.1 to 0.5 MPa. The gap separation was22 mm, and the needle-shaped protrusions were made of stainless steel 10 mm in length and 1.0 mm in diameter. As a result, it was found that the breakdown mechanism and predischarge current are principally dependent on applied voltage waveform and polarity.

• Journal of Trauma and Injury
• /
• 제26권3호
• /
• pp.183-189
• /
• 2013

Purpose: The aim of this study was to identify the optimal insertion angle between the skin and the needle in ultrasound-guided internal jugular vein (IJV) catheterization with trauma patients. Methods: From March 2012 to December 2012, consecutive trauma patients who were planned to receive IJV catheterization were prospectively enrolled. We measured the distances from the skin to IJV's anterior-posterior (AP) vessel wall on the longitudinal scan's midline in supine-positioned patients. We calculated the AP diameter of IJV and the angle between skin and the imaginary line from the puncture site to the IJV's internal center on screen's midline (defined as optimal angle which is considered as the safest approach) on the longitudinal scan. We divided the patients into 3 groups based on the CVP (low CVP <5 $cmH_2O$, $5{\leq}$ middle CVP ${\leq}10\;cmH_2O$, and high CVP>10 $cmH_2O$) and compared their mean anterior posterior (AP) diameters and optimal angles. Results: A total of 56 patients were enrolled. Of these 21 were women(35.4%). The mean AP diameter of low CVP group was significantly lower than middle and high CVP groups($0.68{\pm}0.30$, $1.06{\pm}0.31$, and $1.23{\pm}0.49$ cm respectively, p=0.003 vs. 0.002). There was no significant difference among 3 groups' mean optimal angles ($28.1{\pm}6.1$, $30.1{\pm}4.5$, and $28.0{\pm}5.0$ degree respectively). Conclusion: The optimal angle between the skin and the needle in ultrasound-guided IJV catheterization with trauma patients is not changed as about 30 degrees regardless of CVP even though IJV's diameter is altered in proportion to the CVP.

• 한국산림과학회지
• /
• 제73권1호
• /
• pp.43-54
• /
• 1986

파종상(播種床)에서 피음처리(被陰處理)를 행(行)한 잣나무 유묘(幼苗)의 상대광도별(相對光度別) 생장관계(生長關係)를 분석(分析)하였던 바 기(其) 결과(結果)를 요약(要約)하면 다음과 같다; 1) 신장생장(伸長生長)에 있어서 지상부(地上部)는 상대광도(相對光度) 37% 구(區)에서, 그리고 기외(其外)의 기관(器官)은 100% 구(區)에서 가장 크게 나타났다. 광도(光度)가 지상부(地上部) 및 지하부(地下部), 묘장(苗長), 직경생장(直徑生長)에 미치는 영향(影響)은 기여율(寄與率) 93%, 26.2%, 21.4%. 48.7%였다. 2) 엽령(葉令)에 따라 엽속(葉束) 및 엽장(葉長)의 변화(變化)는 크게 나타났다. 엽속(葉束)은 1년생(年生)의 경우 광도(光度)가 높을수록, 그리고 2년생(年生)은 상대광도(相對光度) 37% 구(區)에서 가장 많았다. 그리고 엽장(葉長)은 각(各) 처리간(處理間)에 큰 차(差)가 없었다. 이때 광도(光度)가 미치는 엽속(葉束) 및 엽령(葉令)에 대(對)한 기여율(寄與率)은 각각(各各) 39%, 27.8% 였고 엽장(葉長)은 2.5%였다. 3) 중량생장(重量生長)은 상대광도(相對光度) 100% 구(區)에서 가장 컸으나 점차 광도(光度)가 낮아짐에 따라 감소(減少)하는 경향(傾向)이었다. 광도(光度)가 미치는 기여율(寄與率)은 생중량(生重量) 및 건중량(乾重量)의 경우 38%와 7.6%였고, 엽건중량(葉乾重量)은 13.18%로 나타났다. 4) T/R 율(率)은 상대광도(相對光度)가 점차 낮아 질수록 증가(增加)하는 경향(傾向)이었다. 이때 광도(光度)가 T/R율(率)에 미치는 기여율(寄與率)은 7.0%였다. 5) 엽건중량(葉乾重量)과 타기관(他器官)의 생장량간(生長量間)에는 정(正)의 상관(相關)을 인정(認定)할 수 있었고 이들간에는 직선회귀(直線回歸) 관계(關係)에 있음도 알 수 있었다.

• 한국분무공학회지
• /
• 제13권4호
• /
• pp.212-219
• /
• 2008

To develop the twin-fluid atomizer having the excellent performance of painting, the spray characteristics of how a wide area can be painted efficiently by one time spraying were studied in this paper. Spray phenomena are affected by the many factors determining the spray field such as the spraying pressure of gas, the spraying pressure and viscosity of liquid paints, the opening duration of needle valve, the design dimension of nozzle, and so on. As the results of experiments, these factors affecting on spray characteristics were suggested as followings; 1) The optimum spraying pressure of gas was $0.015{\sim}0.02\;kPa$, and the appropriate spraying pressure of liquid paint was 0.01kPa, In these situations, the setting up pressures must be compensated as much as the losing amount of pressure because a decompression occurred when operating valves. 2) The duration of opening the needle valve must be sustained for $1{\sim}2$ seconds to inject gas after spraying the liquid paint. This operating of the needle valve was necessary to avoid the affect on the changing of liquid column length, and to prevent the droplet deposit at the initial time of spraying. 3) The spray tip penetration was gained form the experimental equation, and the effective spraying angle was $85^{\circ}{\pm}5^{\circ}$ just at he appropriate spraying pressure of gas. The distribution of the area sprayed had the variation in $350{\pm}50\;mm$ because of the spraying pressure of gas, the its distance from the spray tip, and the lift of the needle valve.

• 한국산림과학회지
• /
• 제76권1호
• /
• pp.1-10
• /
• 1987

잣나무의 유묘기(幼苗期) 생육(生育)에 있어 광(光)과 단근(斷根) 처리(處理)에 따른 이식후(移植後) 생장(生長)에 미치는 몇 가지 영향(影響)에 대하여 조사(調査), 비교(比較) 하였다. 기(其) 결과(結果) 묘목(苗木)의 활착율(活着率)은 상대광도(相對光度)가 낮은 19%구(區)가 가장 높았고, 단근량(斷根量)은 1/2 이상(以上)이 되면 50% 이상(以上)이 감소(減少)되었다. 지상부(地上部), 지하부(地下部) 및 묘경생장(苗徑生長)은 상대광도(相對光度) 100%에서, 그리고 단근(斷根) 1/4 처리구(處理區)가 가장 양호(良好)하였다. 또한 엽속수(葉束數) 및 엽면적(葉面積)은 상대광도(相對光度) 63%구(區)가, 그리고 단근(斷根) 1/4 처리구(處理區)가 가장 크게 나타났다. 따라서 잣나무 유묘생장(幼苗生長)에 미치는 광도(光度)의 영향(影響)은 비교적(比較的) 높았으나 단근량(斷根量)의 효과(效果)는 극(極)히 적게 나타났다.

• Journal of Ginseng Research
• /
• 제4권1호
• /
• pp.16-30
• /
• 1980

In order to increase the production of ginseng, a cultural experiment was carried out under different types of natural forest condition. Seedlings were transplanted with three spacing (70,90 and plants per 1.62m2) under the broad leaved, needle and mixed forest. The obtained results are as follows. 1 Growth of aerial part of ginseng plant. 1) Vegetative growth under forest condition of very poor as compared with ordinary cultivation, but there was no significant in number of leaf and teasel. 2) Stem diameter and stem length under the different forest types were a little difference. However petiole length and number of leafet showed an increasing trend in broad leaved forest as compared with other forest types. 3) The withering date of aerial part of ginseng plant in the needle forest was later than of others. 2. Fresh weight of ginseng root per plant was decreasing in the order of broad leaved forest, needle and mixed forest, needle and sized forest respectively. However the root weight was much smaller than that of ordinary cultivated one. 3. No big difference was observed in the growth of both aerial and root among the planting density 4. Nitrogen content in ginseng root under forest was lower, but calcium content In root was higher than that of ordinary one. 5. Fat and fiber content of ginseng root under forest showed higher than that of ordinary one. 6. The saponin content of ginseng root grown under forest condition was higher than that of ordinary ginseng root. According to high performance liquid chromatogram of saponin, only difference from ordinary cultivated ginseng root was that ginsenoside Re showed higher peak than ginsenoside Rg1.

• 한국산림과학회지
• /
• 제83권4호
• /
• pp.450-459
• /
• 1994

본(本) 연구(硏究)는 최근(最近) 잣나무넓적잎벌의 피해(被害)가 급진적(急進的)으로 확산(擴散)되고있는 경기도(京畿道) 가평군(加平郡)과 강원도(江原道) 홍천군(洪川郡)의 2개(個) 피해임분(被害林分)에 대(對)한 피해해석(被害解析)을 통(通)하여 경제적(經濟的) 피해허용수준(被害許容水準)을 결정(決定)하고 해충(害蟲) 관리(管理)를 위한 종합적(綜合的) 체계수립(體系樹立)의 기초자료(基礎資料)를 얻고자 1984년(年)부터 4개년간(個年間) 실시(實施)하여 다음과 같은 결과(結果)를 얻었다. 1. 임목(林木)의 피해양상(被害樣狀)은 수관(樹冠) 하부(下部) 보다는 상부(上部)에서 심(甚)하게 나타나며 지상부(地上部) 건물질량(乾物質量)의 수직(垂直) 분포(分布)는 건전목(健全木)의 C형(型) 분포(分布)에서 피해(被害)가 증가(增加)할수록 L형(型) 분포화(分布化) 되었다. 2. 잣나무넓적잎벌 피해(被害)로 인(因)한 엽손실(葉損失)은 수고생장(樹高生長)과 직경생장(直徑生長)의 저해(沮害)를 동시(同時)에 일으키며 생장저해(生長沮害)는 엽손실율(葉損失率) 50% 수준(水準)에서 부터 일어나며 이때의 생장감소율(生長減少率)은 10% 내외(內外)였다. 3. 잣나무넓적잎벌 피해(被害)로 인(因)한 직경생장(直徑生長) 감소(減少)는 수관(樹冠) 상부(上部)에서 현저(顯著)하며 하부(下部)로 갈수록 낮은 감소율(減少率)을 보였다. 4. 엽손실(葉損失)에 의한 재적생장(材積生長) 손실(損失)은 피해발생(被害發生) 3년(年) 후(後)인 엽손실율(葉損失率) 50% 범위(範圍)에서 나타났으며 70% 및 90% 피해목(被害木)의 총재적(總材積) 손실율(損失率)은 건전목(健全木)에 비(比)하여 각각(各各) 9%와 20%였다.

• Korean Journal of Radiology
• /
• 제1권4호
• /
• pp.175-184
• /
• 2000

Although surgical resection remains the best option as potentially curative therapy for hepatocellular carcinoma, radiofrequency thermal ablation has begun to receive much attention as an effective minimally invasive technique for the local control of unresectable malignant hepatic tumors. Most recent radiofrequency devices equipped with a powerful generator and larger needle electrode permit larger thermal lesions, up to 5 cm in diameter, with a single ablation. In this article, the author reviews the technical developments and early clinical results obtained with radiofrequency ablation techniques.

• 대한기계학회논문집
• /
• 제12권2호
• /
• pp.308-318
• /
• 1988

본 연구에서는 가압된 액체를 가류실에 접선방향으로 도입하게 함으로써 선회운동에 의하여 미립화를 시키도록 스크류형의 선회분사 노즐을 설계제작하였다.

• 한국연소학회지
• /
• 제15권1호
• /
• pp.1-11
• /
• 2010

In this study, the coupled simulation of fuel injection model and three-dimensional KIVA-3V code was tried to develop an algorism for predicting the effects of varying fuel injection parameter on the characteristics of fuel injection and emissions. The numerical simulations were performed using STAR-CD code in order to calculate the intake air flow, and the combustion characteristics is examined by KIVA-3V code linked with the conditional moment closure(CMC) model to predict mean turbulent reaction rate. Parametric investigation with respect to twelve relevant injection parameters shows that appropriate modification of control chamber orifice diameter, needle valve spring constant and nozzle chamber orifice diameter can significantly reduce NOx and soot emissions. Consequently, it is needed to optimize the fuel injection system to reduce the specific emissions such as NOx and soot.