• Korean Journal of Ichthyology
• /
• v.20 no.1
• /
• pp.7-12
• /
• 2008

Study on spermatid and spermatozoon of a Korean endemic freshwater fish, Microphysogobio yaluensis, has been carried out by transmission electron microscope. Spermiogenesis involves conspicuous modifications intercelluar movement such as centrioles and mitochondria migration, nuclear depression and structural changes for instance chroatin condensation, excess of cytoplasm. The mature spermatozoa are similar to those of other cyprinids as follows: a spherical nucleus with a shallow nuclear fossa, a short midpiece containing several mitochondria and encircling the basal body of the flagellum. However there are some differences in the orientation of the centrioles,the number of the mitochondria and distribution of vesicles from other cyprinids. It could be concluded that the M. yaluensis spermiogenesis belongs to type 2, and its mature spermatozoon is charaterized by a unique feature which may provide a useful systematic character.

• Journal of the Korean earth science society
• /
• v.29 no.1
• /
• pp.29-44
• /
• 2008

This study investigates the influence of the developing and decaying El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) on the relation between typhoon intensity and its formation. From the long-tenn data of 57 years ($1950{\sim}2006$), we first defined the developing El $Ni{\tilde{n}}o$ years and the neutral years. During the developing El Nino years, the typhoon intensity has a strong relationship with formation region of the tropical cyclone, which results in an increase of the accumulated cyclone energy and intensity of energy of typhoon. During the developing El $Ni{\tilde{n}}o$ year based on $Ni{\tilde{n}}o$ 3.4 SST, the locations for the formation of the category 4+5 typhoon move to the eastward region. The genesis potential function and the low-level cyclonic vorticity have an important role on the formation of strong tropical cyclones, which eventually develop as a typhoon class. In this study, the dynamic potential (DP) function (Gray, 1977) and EOF 1 and EOF 2 time series (RMM 1 and RMM 2) of real-time multivariate MJO (Wheeler and Hendon, 2004) are used to measure the genesis potential and the low-level cyclonic vorticity, respectively. To investigate the influence of the developing and decaying ENSO, we defined the Type I case of the decaying El $Ni{\tilde{n}}o$ that turnovers to La Nina, and the Type II case of the recovering years to the neutral condition. During the decaying El $Ni{\tilde{n}}o$ years as Type I, the locations of the strong DP, RMM 1 and RMM 2 move to the westward more prominently to induce retard of the strong typhoon developing.

• Journal of Energy Engineering
• /
• v.23 no.3
• /
• pp.157-162
• /
• 2014

In this research, we investigate electrical performance and electrochemical properties of carbon supported Pt (Pt/C) that is synthesized by polyol method. With the Polyol_Pt/C that is adopted for oxygen reduction reaction (ORR) as cathode of proton exchange membrane fuel cells (PEMFCs), their catalytic activity and ORR performance and electrical performance are estimated and compared with commercial Pt/C(Johnson Mattey) catalyst. Their electrochemically active surface (EAS) area are measured by cyclic voltammetry (CV), respectively. On the other hand, regarding ORR activity and electrical performance of the catalysts, (i) linear sweeping voltammetry by rotating disk electrode and (ii) PEMFC single cell tests are used. The CV measurement demonstrate EAS of Polyol_Pt/C is compared with commercial JM_Pt/C. In case of Polyol_Pt/C, its half-wave potential, kinetic current density are excellent. Based on data obtained by half-cell test, when PEMFC single cell tests are carried out, current density measured at 0.6V and maximum power density of the PEMFC single cell employing Polyol_Pt/C are better than those employing commercial Pt/C. Conclusively, Polyol_Pt/C synthesized by modified polyol process shows better ORR catalytic activity and PEMFC performance than other catalysts.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.9 no.6
• /
• pp.559-565
• /
• 2016

For the purpose of the research, it is analyze the influence traffic Signal Progression on a CBD by expansion of Permissive Left-Turn on the advanced traffic management system program compared with traffic response control For this, divided a average distance between intersections, a traffic network on five district in four city. As the result, Volume of the traffic management system on a advanced traffic management system program compared with traffic response control is effective in traffic signal cycle 160sec 286car per lane, in 140sec 308car, 120sec 264car. As well, for a traffic network as the length of a traffic network 2.0~3.0km, under 2.0km, all of traffic signal cycle(160sec, 140sec, 120sec) a passing band and stop is more effective. But the traffic management system on traffic response control compared with the traffic management system on a advanced traffic management system program is effective in the length of a traffic network over 5.0km. For the efficiency of traffic signal system manage, it should be runned the traffic management system on traffic response control in addition to the traffic management system on a advanced traffic management system program on CBD. As the result of simulation the business in chungju-si, the travel speed of the traffic management system on a advanced traffic management system program is 41.2km/h and the travel speed of traffic response control is 37.5km/h. Therefore, it should be runned per length of a traffic network the traffic management system on traffic response control in addition to the traffic management system on a advanced traffic management system program on CBD.

• Journal of Korean Society of Transportation
• /
• v.23 no.2
• /
• pp.117-130
• /
• 2005

In both deteministic user Optimal Traffic Assignment Model (UOTAM) and stochastic UOTAM, travel time, which is a major ccriterion for traffic loading over transportation network, is defined by the sum of link travel time and turn delay at intersections. In this assignment method, drivers actual route perception processes and choice behaviors, which can become main explanatory factors, are not sufficiently considered: therefore may result in biased traffic loading. Even though there have been some efforts in Stochastic UOTAM for reflecting drivers' route perception cost by assuming cumulative distribution function of link travel time, it has not been fundamental fruitions, but some trials based on the unreasonable assumptions of Probit model of truncated travel time distribution function and Logit model of independency of inter-link congestion. The critical reason why deterministic UOTAM have not been able to reflect route perception cost is that the route perception cost has each different value according to each origin, destination, and path connection the origin and destination. Therefore in order to find the optimum route between OD pair, route enumeration problem that all routes connecting an OD pair must be compared is encountered, and it is the critical reason causing computational failure because uncountable number of path may be enumerated as the scale of transportation network become bigger. The purpose of this study is to propose a method to enable UOTAM to reflect route perception cost without route enumeration between an O-D pair. For this purpose, this study defines a link as a least definition of path. Thus since each link can be treated as a path, in two links searching process of the link label based optimum path algorithm, the route enumeration between OD pair can be reduced the scale of finding optimum path to all links. The computational burden of this method is no more than link label based optimum path algorithm. Each different perception cost is embedded as a quantitative value generated by comparing the sub-path from the origin to the searching link and the searched link.