• 대한조선학회논문집
• /
• 제52권3호
• /
• pp.236-247
• /
• 2015

In this paper, the experimental equipments for ventilated supercavitation in cavitation tunnel is constructed and the basic data of ventilated supercavitation regard to the entrainment coefficient and Froude number is fulfilled. The experiments are conducted for the disk cavitator with injecting air and the pressure inside cavity and the shape of cavity are measured. As the entrainment coefficient increases while the Froude number is kept constant, the ventilated cavitation number decreases to a minimum value which decreases no more even with increasing the air entrainment. The minimum value of ventilated cavitation number, caused by the blockage effect, decreases according to increasing the diameter ratio of test section to cavitator. The cavity length is rapidly enlarged near the minimum cavitation number. In low Froude numbers, the cavity tail is floating up due to buoyancy and the air inside the cavity is evacuated from its rear end with twin-vortex hollow tubes. However, in high Froude numbers, the buoyancy effect is almost negligible and there is no more twin-vortex tubes so that the cavity shape becomes close to axisymmetric. In order to measure the cavity length and width, the two methods, which are to be based on the cavity shapes and the maximum width of cavity, are applied. As the entrainment coefficient increases after the ventilated cavitation number gets down to the minimum cavitation number, the cavity length still increases gradually. These phenomenon can be confirmed by the measurement using the method based on the cavity shapes. On the other hand, when the method based on the maximum width of cavity is used, the length and width of the cavity agree well with a semi-empirical formular of natural cavity. So the method based on the maximum width of cavity can be a valid method for cavitator design.

• Animal cells and systems
• /
• 제14권2호
• /
• pp.137-145
• /
• 2010

Four specimens of unknown Coilia sp. were collected for the first time from the Yellow Sea in 2008 and compared with Coilia mystus and Coilia nasus. Coilia sp. showed similar morphology to C. mystus and C. nasus, but differed in that its tail was considerably shorter. We conducted an analysis of the morphological and genetic characteristics in an effort to clarify the taxonomic position of Coilia sp. In counts and measurements, Coilia sp. were well distinguished from C. nasus by the number of scutes (42-44 in Coilia sp. vs. 40-45 in C. mystus vs. 45-55 in C. nasus), ratio of dorsal base length to head length (43.4-47.6 vs. 37.9-47.6 vs. 33.0-41.0), and eye length to head length (19.2-20.8 vs. 17.0-22.4 vs. 13.8-18.2). In caudal skeleton of Coilia sp., urostyle, hypural and epural bones were not observed; instead of them, caudal fin rays were supported by the last vertebra, neural and haemal spines' extension. The molecular phylogenetic relationship was analyzed using 414 base-pair 12S rRNA mitochondrial DNA sequences. The Kimura-2-parameter distance between Coilia sp. and C. mystus was 0.3%, but was 1.3% between Coilia sp. and C. nasus. Both the neighbor-joining tree and maximum-likelihood tree showed that Coilia sp. are closely clustered with C. mystus. Therefore, our results suggest that the Coilia sp. may be a deformed fish of C. mystus.

• 한국어류학회지
• /
• 제35권4호
• /
• pp.378-383
• /
• 2023

우리나라 전 해안을 대상으로 미끈망둑 (Luciogobius guttatus)에 대한 분류학적 재검토를 실시하였다. 그 결과 41개체 (31.3~54.4 mm SL)가 L. martellii로 분류되었다. 본 종의 형태학적 특징은 다음과 같다: 복추골 수 16개; 총 척추골 수 35~37개; 등지느러미 기저부의 길이가 미병부 상부의 길이보다 길거나 같음; 가슴지느러미 상부에 1개의 유리연조; 꼬리지느러미 끝이 하얀색인 특징이 있다. 그중에서 L. guttatus와 형태학적으로 가장 뚜렷한 차이점인 등지느러미 기저부 길이와 미병부 상부의 길이의 차이는 L. martellii의 총모식표본과도 잘 일치하였다. 본 종의 한국명으로 "검정미끈망둑"을 제안한다.

• Journal of Ecology and Environment
• /
• 제37권4호
• /
• pp.201-208
• /
• 2014

To date, no study has reported detailed morphological characteristics of Korean sea turtles. Due to the lack of such basic information on Korean sea turtles, further related studies have been difficult in South Korea. In this report, we determined the species and the sex of the one sea turtle caught from the Yellow Sea of Korea (Taean-gun, Chungcheongnamdo) on July 17, 2013, and described its detailed morphological characteristics. The sea turtle was identified as a loggerhead sea turtle (Caretta caretta) by the presence of an interprefrontal scale on the head. The turtle had three times longer length between the edge of anal scute to the anus than that between the anus to tip of the tail, and the size of a pair of claws on the flippers were distinctively different, suggesting that the turtle was a male. Finally, the assumption that the sea turtle might be sexually mature is based on its body weight (59.95 kg), the maximum straight length of the carapace (72.5 cm), and the worn serrated parts at the edge of supracaudal scutes. The loggerhead sea turtle described in this study is the first record from the Yellow Sea of Korea.

• Ocean and Polar Research
• /
• 제26권4호
• /
• pp.685-688
• /
• 2004

The morphology of the post-larva of Liopropoma japonicum of the family serranidae is described from one specimen collected off Jeju Island ($32^{\circ}42'N,\;127^{\circ}45'E$) on May 3, 2001. The body is laterally compressed and caudal peduncle deep at 19.4 mm BL. Anus locates at a vertical through posteriormost(8th) dorsal-fin spine. Dorsal fin rays were VIII, 14; anal fin rays III, 10; pectroal fin rays 16; pelvic fin rays I, 5. A caudal fin is rounded. Length of elongate second and third dorsal-fin spines are 499% and 423% of the body length, respectively. A series of 50 sensory pores on body is elongated to caudal fin. Head spination is well developed. Melanophores are moderately large and dense in the head, and are small and rare in teh neck. Being freshly collected, the body color is yellowish-red and tail is semitransparent. The head is yellowish-red and the brain is dark-red.

• 경영과학
• /
• 제25권2호
• /
• pp.81-88
• /
• 2008

This paper presents a new algorithm for the K shortest paths problem in a network. After a shortest path is produced with Dijkstra algorithm. detouring paths through inward arcs to every vertex of the shortest path are generated. A length of a detouring path is the sum of both the length of the inward arc and the difference between the shortest distance from the origin to the head vertex and that to the tail vertex. K-1 shorter paths are selected among the detouring paths and put into the set of K paths. Then detouring paths through inward arcs to every vertex of the second shortest path are generated. If there is a shorter path than the current Kth path in the set. this path is placed in the set and the Kth path is removed from the set, and the paths in the set is rearranged in the ascending order of lengths. This procedure of generating the detouring paths and rearranging the set is repeated until the $K^{th}-1$ path of the set is obtained. The computational results for networks with about 1,000,000 nodes and 2,700,000 arcs show that this algorithm can be applied to a problem of generating the detouring paths in the metropolitan traffic networks.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회 2006년도 추계학술대회
• /
• pp.60-66
• /
• 2006

This paper presents a new algorithm for the K shortest path problem in a directed network. After a shortest path is produced with Dijkstra algorithm, detouring paths through inward arcs to every vertex of the shortest path are generated. A length of a detouring path is the sum of both the length of the inward arc and the difference between the shortest distance from the origin to the head vertex and that to the tail vertex. K-1 shorter paths are selected among the detouring paths and put into the set of K paths. Then detouring paths through inward arcs to every vertex of the second shortest path are generated. If there is a shorter path than the current Kth path in the set, this path is placed in the set and the Kth path is removed from the set, and the paths in the set is rearranged in the ascending order of lengths. This procedure of generating the detouring paths and rearranging the set is repeated for the K-1 st path of the set. This algorithm can be applied to a problem of generating the detouring paths in the navigation system for ITS and also for vehicle routing problems.

• Journal of Species Research
• /
• 제5권3호
• /
• pp.547-550
• /
• 2016

Hemicycliophora litoralis is newly collected from Korea. Korean population is well matched and within a range of original description and additional record from Solomon island in de Man's of L, b, c, V, R, Rex, Ran, Roes, RV (ant), annule, excretory pore, stylet length, and tail length. Differences are observed in RV and RVan. RV and RVan of original description was 55 (48-69) and 14 (10-19) but Korean population is 68 (61-76) and 22 (19-24), respectively. H. litoralis described from Solomon island has RVan of 19.6 (17-23) and is similar to Korean population. H. litoralis from Solomon island has slight higher Rst value of 39 (35-59) compared to Korean population of 33.5 (29-38). The measurements of MB (%), s, G1, G2 values are newly given.

• The Plant Pathology Journal
• /
• 제24권3호
• /
• pp.361-364
• /
• 2008

The complete nucleotide sequences of a Korean isolate of Potato virus X(PVX-Kr) has been determined. Full-length cDNA of PVX-Kr has been directly amplified by long template reverse transcription and polymerase chain reaction(RT-PCR) using virus specific 5'-end primer and 3'-end primer, and then constructed in a plasmid vector. Consecutive subclones of a full-length cDNA clone were constructed to identify whole genome sequence of the virus. Total nucleotide sequences of genome of PVX-Kr were 6,435 excluding one adenine at poly A tail, and genome organization was identical with that of typical PVX species. Comparison of whole genome sequence of PVX-Kr with those of European and South American isolates showed 95.4-96.8% and 77.4-77.9%, in nucleotide similarity, respectively. Sequenced PVX-Kr in this study and twelve isolates already reported could be divided into two subgroups in phylogeny based on their complete nucleotide sequences. Phylogenetic tree analysis demonstrated that PVX-Kr was clustered with European and Asian isolates(Taiwan, os, bs, Kr, S, X3, UK3, ROTH1, Tula) in the same subgroup and South American isolates(CP, CP2, CP4, HB) were clustered in the other subgroup.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
• /
• pp.27-36
• /
• 1999

To have high flatness quality of hot rolled strip in the hot strip finishing mill train, a new inter-stand tension profile measuring device of segmented looper roll type(coined as Flatness Sensing Inter-stand Looper, FlatSIL) and a new flatness control system have been developed in this study. The device measures the strip tension profile across the strip width and informs the strip wave pattern to new flatness control system where work roll bending mode to relieve the strip wave is determined. The existing automatic shape control system which uses laser type shape-meter installed at the outlet of the last finishing mill stand strip tension between down coiler and last finishig mill since the latent wave concealed by the strip tension between down coiler and last finishing mill stand cannot be measured by the laser distance-meter. Thus the existing shape control system is not able to control the flatness through the full strip length. The new flatness control system, however, works for full strip length during strip rolling as far as the tension profile measuring device and work roll bender are on. With the new flatness control system, work roll bender is automatically controller to minimize the latent wave of the running strip and the flatness quality as well as strip travelling stability has been noticeably improved from strip head through body to tail.