• Journal of Mechanical Science and Technology
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• v.14 no.12
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• pp.1396-1402
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• 2000

Here is investigated the characteristics of double-diffusive convection in thermally-stable stratified horizontal fluid layer. By employing an electrochemical technique, and adopting aqueous CuSO$_4$-H$_2$SO$_4$solution as electrolyte, experiments on ionic mass transfer have been conducted systematically. And, also a new mass transfer correlation in double-diffusive situations has been derived by extending the model of micro-scales of turbulence, which was proposed by Arpaci. The resulting correlation of the Sherwood number as a function of the thermal Rayleigh number was in good agreement with the present experimental results. The present study provides plausible understanding in controlling both mass and heat transfer rates for practical situations including double-diffusive convection.

• Korean Journal of Veterinary Service
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• v.13 no.1
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• pp.90-95
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• 1990

1) During 5 month(Oct. 1988-Feb. 1989), abortion(11 heads), stillbirth(3 heads), and congenital abnormalities(28 heads) of newborn were occurred in 42 milk cows raised in Cheju island. These cows were diagnosed with Akabane disease by clinical, pathological and serological test. 2) In May and Oct. 1989, 213 tattles at 10 farms were investigated on the actual condition of possessing Akabane antibody. The results was that 210 heads(98.6%) in 213 cattles reacted as positive condition in Akabane antibody. The antibody titer was from 4 to over 256. 3) During some years, the author suppose that the vaccination for Akabane disease will be unnecessary because of higher positive antibody reaction except the newly introduced cattle.

• Journal of Energy Engineering
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• v.10 no.3
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• pp.266-271
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• 2001

Buoyancy-driven natural convection is analysed by employing a linear stability theory in hori-zontal porous media with net through flow. Darcy's law is used to model the flow characteristics in porous media. Bated on the results of linear stability analysis, a heat transfer correlation was obtained by employing weakly nonlinear analysis. As the net through flow increases, the system becomes more stable and the effect of the Darcy-Rayleigh number on the Nusselt number decreases.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.173-175
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• 2005

Malfunction of Klippon relay in Cheju-Haenam HVDC system has been caused by the inflow of high voltage arc. In this paper, we have studied on the theoretical examination and data analysis of Klippon relay, and the countermeasures against the problems were suggested according to their causes. Grounding problem in Klippon relay is removed by one-point earth connection and by modification of grounding circuit. The effects of over current surge was removed by attaching blocking diodes by series In Klippon relay to remove surge input in Klippon relay's mercury contact. The problem of Induced overvoltage by 86re1ay excitation coil, was removed by attaching Free-wheeling diode in parallel with the excitation coil of Lock-out relay.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.845-851
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• 1998

In order to manage the water quality from the flowing streams in Cheju Island, the characteristics of water quality was investigated from August, 1996 to May, 1997 and the pollutant loadings for future were estimated from the watershed at each stream. Comparing the mean concentrations of each water quality with the criterion of water quality in river, it was under I class except for Changgo Stream, for DO, under I class at the whole station for SS and under II class for BOD. As the pollutant loadings at each stream in 2020 is compared with those in 1996, the estimated results are as follows : 1) for BOD, 59% at Donghong Stream, 24% at Yeonoe Stream, 44% at Ohngpo Stream and 57% at Changgo Stream. 2) for T-N, 91% at Donghong Stream, 76% at Yeonoe Stream, 63% at Ohngpo Stream and 89% at Changgo Stream. 3) for T-P, 69% at Donghong Stream, 42% at Yeonoe Stream, 45% at Ohngpo Stream and 73% at Changgo Stream. The point source loadings discharged through combined sewer could be treated at sewage treatment plant. However, the expected slow decreasing rate of BOD, T-N, and T-P loadings is due to the part of untreated nonpoint source loadings. Nonpoint source loading overflow typically occurs when the flow of stormwater combined with sewage exceeds the capacity of the interceptor sewers. Since most of the sewers used in Cheju Island are the combined sewers, the combined overflow sewage is bypassed into the receiving water area after a rainstorm. Therefore, a means to control nonpoint source loadings should be considered for the river and marine water quality management.

• The Journal of the Petrological Society of Korea
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• v.2 no.2
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• pp.139-155
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• 1993

We have shown that the volcanic rocks from the northern part of Cheju Island can be divided into high $P_2O_5/K_2O$(HPK) and low $P_3O_5/K_2O$(LPK) groups, each with distinct geochemical characteristics(Park and Kwon, 1993a and b). This study reports mineral compositions for plagioc-lase, olivine, and clinopyroxene in order to see the dependence of mineral chemistry on the whole rock composition, and discusses equilibrium relationships between crystal and liquid. Plagioclase and olivine phenocrysts show no compositional differences for the two rock group. However, $Al^{ⅵ}/Al^{ⅳ}$ ratios of clinopyroxenes suggest that pyroxenes have fractionated at deeper level, and that the LPK group might have fractionated at higher pressure than the HPK group. These are in good agreement with our previous interpretation based on whole rock chemistry(Park and Kwon, 1993a). Although subhedral or euhedral form and homogenous composition for most plagioclase and clinopy-roxene phenocrysts suggest equilibrium relationship with liquid, the uncertainties associated with liquid, the uncertainites associated with equilibrium constant for these minerals do not allow testing equilibium relationship between mineral and liquid on the basis of chemistry. On the other hand, olivine phenocrysts in hawaiites, for which Kd is well known, show distinct nonequilibrium relationship with calculated liquid composi-tions, while those in other rock compositions are in equilibrium from those for other rocks. We report for the first time as far as we know plagioclase xenocryst and pigeonite inclusion in plagioclase, which indicates assimilation process. In conclusion, these mineralogical observations imply that mag-matic processes underneath the Cheju volcano were not simple.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.57-63
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• 2008

Recently, OGC(Open Geospatial Consortium) take the lead in SWE(Sensor Web Enablement) research that collection various context information from sensor networks and show it on map by web. OGC SWE WG(Working Group) defines a standard encoding about realtime spatiotemporal appear geographical feature, sensing data and support web services. This paper proposes a visualization scheme of sensing data based location on 2D maps. We show realtime sensing data on moving node that mapping GPS data on map. First, we present an algorithm and procedure that location information change to position of maps for visualization sensing data based on 2D maps. For verifying that algorithm and scheme, we design and implement a program that collecting GPS data and sensing data, and displaying application on 2D maps. Therefore we confirm effective visualization on maps based on web which realtime image and sensing data collected from sensor network.

• 한국해양학회지
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• v.28 no.2
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• pp.114-120
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• 1993

Numerical method of nonlinear regression was introduced to characterize grain-size distribution more effectively than using the traditional textural parameters. This technique proved critical particularly to multimodal size distributions, as exemplified by samples from Cheju strait continental shelf. Grain-size analysis of samples collected from the Cheju Strait continental shelf reveals that 86% of the grain-size distributions are multimodal. As multimodal grain-size distribution deviates from the statistical (log) normal distribution, the grain-size parameters traditionally used in sediment studies do not describe the distribution efficiently. Therefore, the use of grain-size curves into elementary normal component curves was used. Means and standard deviations of 387 decomposed normal components were decided by a decomposition method (nonlinear least square regression) from 167 size curves of the Cheju Strait sediments. The mean values of decomposed normal components show peaks at 1-3 phi and 8-9 phi size classes. The plot of mean values of the coarse fraction normal components on the map shows a characteristic and complex areal distribution. On the basis of the areal distribution of the mean values of the components and that of isopach of total Plenipotence sediment, the areal distribution of layers composing a transgressive sand of Late Plenipotence age were revealed.

• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.58-65
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• 1986

The results from a survery on the reproduction of a, pp.oximately 500 dairy cows raised in four different farming areas including Cheju city, Jochun, Hallim and Sung-up are summarized as follows; 1. At the occurrence of first estrus, the average age of the heifers was 15.1 months (330 Kg/B.W.), and at first conception 18.0 months (354Kg/B.W.). There was no regional differences. 2. The average interval of the estrous cycle was 20.4 days. And the repetition of esturs after unsuccessful insemination occurred on an average of 1.6 times, especially 2.0 times in the herds of the Jochun district. 3. The ages at the first calving were similar to the data recorded for the domestic mainland's herds at 27.1 months. But some regional differences were recognized within the four districts: i.e. 28.6 (Cheju city), 27.4(Jochun), 27.1(Hallim) and 25.3 months (Sung-up). There was no significant differences in sex ratio of newborns at 50.4%(♂) and 49.6%(♀). 4. The intervals of esturs recurrence and the following conception after calving were 80.0 and 95.8 days respectively. In the followsing conception intervals after cavling, 90.6-97.4 days were average for the herds of Cheju city and Jochun districts, 62.4-69.7 days for those of Hallim and Sung-up districts. 5. The average gestation period was 279.8 days, and was almost identical in the four districts. 6. The calving intervals was 377.7 days in average, and it was shorter than the data recorded for the domestic mainland's herds. Also it was reduce gradually according to the calving frequency.

• Korean Journal of Plant Taxonomy
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• v.34 no.4
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• pp.359-364
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• 2004

Sedum tosaense Makino (Crassulaceae), an unrecorded species in Korean flora, was collected from parasitic crater, Sangumburi in Jocheon-eup Bukjeju-gun, Jeju-do. This species is most similar to S. bulbiferum and S. orizifolium, but differs in some substantial characters. S. tosaense is perennial and stoloniferous herb with bulbils on stems, while S. bulbiferum is annual or biennial herb without bulbils in leaf axil. In addition, S. tosaense has leaves emarginate at apex whereas S. bulbiferum has leaves somewhat uneven at apex. the leaves of S. tosaense are conspicuously flattened and spatulate in shape at the stem without flowers, but those of S. orizifolium, are terete or slightly flattened and linear to narrowly oblong in shape.