• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 추계학술대회 논문집 전력기술부문
• /
• pp.158-160
• /
• 2006

The role of SVL (Sheath voltage limiter) in cable system is to protect the PVC(or PE) jacket in case of transient overvoltage resulting from lightning and other causes. But, in Korea, there is so many SVL failure cases resulting from power frequency overvoltage. So, the paper investigates the phenomenon of failure SVL comparing with other countries' system. Finally, the installation of ECC(Earth Connectivity Conductor) in under ground cable system is presented to remove the possibilities of SVL thermal runaway due to the power frequency overvoltage.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 제39회 하계학술대회
• /
• pp.470-471
• /
• 2008

SVL is installed at underground transmission system to protect cables and insulation joint-box from overvoltages caused by lightning, switching, and line-to-ground fault. Domestic underground power system adopts cross bonding type to reduce the induced voltage at sheath, but single-point bonding is required depending the system installation configuration. SVL can be easily broken by overvoltages induced at joint-box because single-point bonding has uneffective system structure to extract fault current. ANSI/IEEE recommends Parallel Ground Continuity Conductor(PGCC) to prevent SVL breakdown. In this paper, EMTP simulation is performed to analyze effects on SVL under PGCC installation when single-line-to-ground fault occurs. The result shows that PGCC and short single-point bonding distance can reduce overvoltages at SVL.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
• /
• pp.119-121
• /
• 2008

In underground power cable system, the device for limiting over-voltage is needed when transient over-voltage break out between sheath and ground. For this reason, the SVL(Sheath Voltage Limiter) has been applied on weak points. But the broken SVLs which are installed on the single point bonding system on underground cable are frequently found. In this paper, EMTP(Electromagnetic Transient Program) is utilized to analyze effects on the installation methodology of the parallel ground conductor and SVL for the single point bonding system on the underground cable. The result shows that the proposed installation methodology can be applied for single point bonding system and contribute for power system stabilization.

• Journal of Ecology and Environment
• /
• 제33권4호
• /
• pp.325-331
• /
• 2010

In this study, we have evaluated the physical characteristics of neonate, female, and male Mongolian racerunners (Eremias argus) and determined the age structure of a population of the species in a field located in Taean-gun, Chungnam, South Korea. The physical parameters of females and males, including snout-vent length (SVL), head length, head width, and body mass were found to be significantly interrelated. Male Mongolian racerunners exhibited significantly longer heads than the females, but other physical parameters, such as SVL, head width, and body mass did not differ between the female and male specimens. In the study population, the females ranged in age from two to eleven years old and the males ranged between two to eight years of age. The number of females and males, when separated into different age classes, did not differ within each age class. Male Mongolian racerunners evidenced greater SVL growth coefficients than the females, but asymptotic SVL did not differ between the females and males.

• The Korean Journal of Ecology
• /
• 제25권1호
• /
• pp.25-28
• /
• 2002

The advertisement call of anurans functions to attract potential mates. The dominant frequency of an advertisement call is generally getting lower with increased snout-vent length (SVL) of the caller Rana rugosa has an advertisement call tilth a particularly high frequency modulation. We conducted a playback experiment to verify the function of frequency modulation, and investigated the territorial behavior of the frog. The frog has five types of territory defense strategy. Strategy choice depended on the caller's SVL. Small males became satellites or lowered the dominant frequency of their advertisement call, whereas large males actively defended their territory with encounter calls. In response to high frequency (1107 Hz) playback, the frogs lowered their advertisement call frequency, and towered them further in response to the low frequency (1028 Hz) playback. In addition, the number of pulses in a call was increased in response to the playback. These results indicate that the frog avoids physical conflict with competitors by selecting a territory defense strategy suitable for the caller's size, and by lowering its call frequency to disguise its SVL.

• 한국환경생태학회지
• /
• 제26권5호
• /
• pp.668-674
• /
• 2012

본 연구는 한국에 서식하는 장지뱀과 3종인 표범장지뱀(Eremias argus), 아무르장지뱀(T. amurensis), 줄장지뱀(T. wolteri)의 외부 형질에 대한 성적 크기 차이(SSD)를 알아보기 위하여 수행되었다. 외부 형질 중 주둥이-항문 길이, 꼬리 길이, 머리 길이, 머리 폭, 앞다리 길이, 뒷다리 길이와 같은 6개 부위를 중심으로 수컷과 암컷을 비교하였다. 머리-항문 길이는 student's t 검정을, 나머지 부위는 머리-항문 길이를 공변량으로 이용하여 공분산 검정을 수행하였다. 머리 길이와 꼬리길이는 일반적인 장지뱀과의 특성과 마찬가지로 한국산 장지뱀과 3종 모두 수컷이 암컷보다 긴 것으로 나타났다. 추가적으로 표범장지뱀은 머리 넓이, 앞다리 길이, 뒷다리 길이, 줄장지뱀은 머리 넓이에서 수컷이 암컷보다 길었다. 머리-항문 길이는 한국산 장지뱀과 3종 모두 암 수 사이에서 유의한 차이가 없었다. 머리-항문 길이의 SSD의 원인을 파악하기 위해서는 수컷간의 싸움과 암컷 머리-항문 길이와 한 배 산란수의 관계와 같은 생태학적 정보가 필요하다. 한국산 장지뱀과 3종에 대한 생태학적 연구가 계속 진행된다면 SVL에서 SSD가 일어나지 않은 이유를 설명할 수 있을 것이다.

• 한국환경생태학회지
• /
• 제25권6호
• /
• pp.861-866
• /
• 2011

우리는 제주도 대정읍에서 뼈나이테법(skeletochronology)을 사용하여 맹꽁이(Kaloula borealis)의 나이구조를 알아보았다. 조사는 번식기인 2009년 6월에 실시하였다. 측정된 개체수는 수컷이 38개체, 암컷이 58개체로 각 개체의 SVL(snout-vent length)과 체중을 측정하고 나이구조를 분석하였다. 수컷의 평균 SVL은 $43.69{\pm}3.44 mm$이며, 암컷은 $46.32{\pm}4.23mm$로 나타나고 있다. 첫 번식에 참여하는 수컷은 2살이고, 암컷은 3살로 나타났다. 가장 나이든 수컷은 8살이며 암컷은 10살이다. 그러므로 이 종의 수명은 수컷에서는 8살, 암컷에서는 10살 이상으로 볼 수 있으며 암수의 수명에서 암컷이 더 오래살고 있다. 또한 이 값은 통계적으로도 유의미하게 나타나고 있다. 성장곡선은 von Bertalanffy growth model을 사용하였으며, 성장계수(K)는 수컷이 0.56이며 암컷은 0.41이다. 최대성장크기는 수컷이 46.41 mm이며 암컷은 50.22 mm로 나타났다.

• Journal of Ecology and Environment
• /
• 제31권3호
• /
• pp.183-191
• /
• 2008

To determine the age structure of a Hynobius leechii breeding population and analyze relationships between the order of entrance to breeding ponds and physical parameters and age, we studied a wild population of the species in the Research Forests of Kangwon National University in Chuncheon, Kangwon, South Korea from March 16 to April 13, 2005. The age of breeding males ranged one to nine years old and that of females ranged from three to nine years old. The asymptotic sizes of males and females were 6.36 and 6.51 cm, respectively, and the growth coefficients of males and females were 0.71 and 0.81, respectively. The snout-vent length (SVL), head length, and body mass of males were all positively correlated with their age, but female age did not show a significant relationship with any physical parameter. The tail depth, body mass, and condition factors (SVL/body mass $\times$ 100) of both males and females were negatively related with the order of entrance to the breeding pond. The head width and SVL of males were also negatively correlated with the order of entrance, but the SVL of females was positively related with the order of entrance. These results suggest that physical parameters are more important determinants of breeding migration patterns than age. We discuss which of two hypotheses, the mate opportunity hypothesis and the susceptibility hypothesis, is better able to explain the order of entrance to breeding ponds for male and female H. leechii.

• 전기학회논문지
• /
• 제63권6호
• /
• pp.764-769
• /
• 2014

This paper describes sheath voltage limiter(SVL) transient characteristics by switching overvoltage considering single point bonding in underground transmission cables. The crossbonding system is generally used for grounding methods of underground transmission system. However, the single point bonding system is used in selective area which is difficult to consist of crossbonding major section. The sheath voltage limiters are connected between joints in the single point bonding. Specially, the high overvoltage might be generated in that section as well as the aging of sheath voltage limiter might be progressed by various electrical stress including lightning overvoltage, switching overvoltage and power frequency overvoltage. Therefore, in this paper, the switching overvoltage characteristics in underground cables are firstly analysed using EMTP simulation. Then, the switching overvoltage of sheath voltage limiter is also studied in single point bonding. Finally, the reduction method of sheath voltage limiter switching overvoltage is proposed by various simulation studies including circuit breaker operating order.

• Journal of Chest Surgery
• /
• 제19권1호
• /
• pp.43-49
• /
• 1986

At the Department of Thoracic and Cardiovascular Surgery, Hanyang university, from 1976 to 1984, 102 patients operated for isolated patent ductus arteriosus were studied. The correlation between the degree of left ventricular hypertrophy [LVH] and hemodynamic data, and postoperative changes of electrocardiographic findings were evaluated. The following results were obtained; [1] Of 102 patients with isolated patent ductus arteriosus, 78 patients [76.5%] were found to have LVH by EKG, preoperatively. [2] The patients with LVH had higher incidence of respiratory infection [79.4%] compared to patients without LVH. [3] Frequent physical findings in the patients with LVH were precordial bulging and P2 accentuation on auscultation. The typical continuous machinery murmur was not different in two group with or without LVH. [4] 66.1% of patients with LVH showed more than 56% of cardiothoracic ratio [CTR] on simple chest X-ray. 56.5% of patients without LVH showed less than 50% of CTR. [5] In the patients found to have LVH by EKG, the correlation between values of Svl+Rv6 and Qp/Qs in hemodynamic data was correlation coefficient 0.57 and between CTR and Qp/Qs was correlation coefficient 0.51. [6] In patent ductus arteriosus with LVH following surgery, the values of Svl+Rv6 was changed from preoperative 153.6$\pm$42.78% to 107.7$\pm$19.58% within 3 months and to 80.4$\pm$12.22%, which is within normal range of Svl+Rv6 on EKC, after 6 months.