• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.886-889
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• 2002

In order to evaluate absorption coefficient, experimental works for normal and random incident absorption coefficient are made. An investigation for correlation between normal and random incident absorption was carried out by experiment and analysis. It appears that at the low frequencies, the random incident absorption is higher than the normal one, whileas at the high frequencies, the random incident absorption is decreased due to the effect of grazing incident components.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.478-485
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• 1998

The interior of open cavities exposed to a grazing flow is known to experience, strong periodic pressure, oscillations sustained for a wide range of flow velocities. In this study, an original approach was followed to develop a describing function model for the flow-excitation mechanism, governed by the shedding of discrete vortices within the shear layer over the orifice. A feedback loop analysis was performed to predict the frequency and the amplitude of the interior pressure fluctuations. Furthermore, a limit cycle stability analysis based on the extended Nyquist Stability criterion allowed the predictions of the onset and termination velocities for various modes. The analytical model was verified experimentally.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.3
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• pp.158-162
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• 1989

This experiment was conducted to evaluate individual difference of chewing speed and chews per bolus duing the rumination using twenty three heads of grazing cattle and thirty six heads of barn feeding cattle. Rumination behaviour was measured and recorded by the masster EMC telemeter and visual observation. The chewing speed (chews/lOOsec) was significantly different individually (C.V. 13.0-14.5 %) among the variable aged group (1-60 months), but that of same aged group showed lower difference (C.V. 4.5 %). The chews per bolus showed even larger individually difference than the chewing speed, so the variable aged group (1-60 months) resulted the 15.5-16.2 %of C.V.and the same aged group showed the 9.5 % of C.V. Under 12 month aged cattle showed more rapid chewing speed than older aged cattle. The chewing speed changed with the growth of cattle, but the chews per bolus did not show any relationship with age, so it is regarded as the individually characteristic pattern.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.192.2-192.2
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• 2013

Crystalline order and surface stability of 1,4,5,8,9,11-hexaazatriphenylene-hexanitrile (HATCN) thin films on organic surface were investigated using grazing incidence wide angle x-ray scattering and x-ray reflectivity measurements. In the initial growth regime (less than 20 nm), HATCN molecules were stacked to low crystalline order with substantial amorphous phase. Meanwhile, a thicker film with 50 nm thickness showed high crystalline order of hexagonal phase with three different orientational domains. The domain distribution was quantitatively obtained as a function of tilted angle. By an organic-inorganic interface formation of IZO/HATCN thin film from an indium zinc oxide (IZO) electrode deposition, the surface stability of HATCN film was investigated and the sharp interface was confirmed by the x-ray reflectivity measurement.

• Proceedings of the Korean Society of Grassland Science Conference
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• 2005.06a
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• pp.222-223
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• 2005

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.4
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• pp.229-239
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• 2009

To understand major factors that affected on distinct Cochlodinium bloom scale in Korean coasts in 2007 and 2008, oceanographic and meteorological characteristics during Cochlodinium bloom period were compared. The main reason for large scale blooms in 2007, covering both southern coast and eastern coast with about 10 million US dollars fish kills, was attributed to sufficient nutrient supply by heavy rainfall, upwelling in the coast arising from irregular wind shift, weak thermocline and low grazing pressure by zooplanktons during Cochlodimum bloom development period. On the contrary, small scale blooms in 2008 covering only inshore areas of southern coast without fish kills was attributed to the low nutrient level in coastal areas by long persistent drought and strong influence of oligotrophic offshore water onto inshore and high grazing pressure by extra ordinarily abundant zooplanktons during Cochlodinium development period. Conclusively, it was estimated that nutrient level, strength of offshore water and feeding pressure might play a significant role in the difference of bloom scale between the two years.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.285-293
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• 2016

In the paper, we propose a data transmission repeating system that allows data transmission for the effective supervision of cows grazing in the pasture. It is normal practice to divide the pasture into different areas for the purpose of distributing the grazing. However, this makes it difficult to supply electrical power and transmit data, because some of the pastures are far away from the office used for collecting data. To solve this problem, we developed a repeating system that can allow data transmission in the pasture using a solar charging system that consists of a 60W solar panel, 12V/100A battery and 6A solar controller for the power supply and a data transmission algorithm which extends the range of data transmission when using the proposed repeating system. We verified the performance of the repeating system by checking whether the data transmission is successful or not when transmitting from various test points when there is an obstacle between the receiver and repeating system. We also verified the solar charging system by measuring the battery voltage when the system is operated continuously for 31 days and whether the system can supply sufficient power when the weather is cloudy or rainy for a few days. Finally, we verified the performance of the repeating system and data transmission algorithm by conducting experiments in a pasture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.3
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• pp.262-270
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• 2012

Seaweeds provide habitats in which marine animals can spawn and develop, and serve as a food supply for algaegrazing species such as sea urchins and abalone. Recently, seaweed species have disappeared from coastal ecosystems, leaving barren ground, defined as habitats that have lost their algae forests and where coralline algae containing calcium carbonate components have become encrusted on rocks. The biological causes of barren ground include grazing by herbivores and excessive seaweed harvest. The environmental harm caused by the spread of barren ground includes accelerated eutrophication following the reduction in seaweed, which plays an important role in oceanic purification. In the present study, we identified the relationships between various seaweed species and the occurrence of barren ground. Subtidal benthic macroalgal flora and community structure were observed seasonally on barren ground along vertical transects of rocky shores of Bihwa, Samchuck, and the east coast of Korea from February to November 2006. Fifty-eight seaweed species were identified, including 7 green, 15 brown, and 36 red algae species. There were between 6 and 28 species among seasons. Over the whole study period, average seaweed biomass (g wet wt $m^{-2}$) was 241.90 g, with a seasonal range of 25.26 to 760.34 g. Seaweed biomass declined with increasing seawater depth and ranged between 91.26 and 422.08 g. The vertical distribution of algae was characterized by Undaria pinnatifida and Sargassum honeri at 5 m, S. honeri and U. pinnatifida at 10 m, and U. pinnatifida and Agarum clathratum at 15 m depth. Seasonal patterns in community indices were not found. Community indices showed different patterns along vertical shoreline gradients; the dominance index increased but the richness, evenness, and diversity indices decreased with seawater depth. Sea urchin density was 8 to 24 individ. $m^{-2}$ in Bihwa. These urchin populations had significantly aggregated spatial patterns and recurrent destructive grazing appeared to be occurring.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.181-188
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• 2004

The contaminative influence of beef due to the inhalation of air and the ingestion of soil of livestock, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was comprehensively investigated with the improvement of the Korean food chain model DYNACON. As the results, it was found that both pathways can not be neglected at all in the contamination of beef in the case of an accidental release during the non-grazing period of livestock. The ingestion of soil was more influential in the contamination of beef than the inhalation of air over most time following an release. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was far greater compared with the cases of no precipitation. This fact was more distinct for a long-lived radionuclide $^{l37}Cs$ than a short-lived radionuclide $^{131}I$ (elemental iodine). Compared with the results for milk performed prior to this study, the contaminative pathways due to the inhalation of air and the ingestion of soil were more important in beef because of longer biological half-lives. On the other hand, in the case of an accidental release during the grazing period of livestock, radioactive contamination due to the ingestion of pasture was dominant irrespective of the existence of precipitation during an accidental release. It means that contaminative influence due to the inhalation of air and the ingestion of soil is negligible, like the cases of milk.

• ALGAE
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• v.29 no.2
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• pp.137-152
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• 2014

Mixotrophic protists play diverse roles in marine food webs as predators and prey. Thus, exploring mixotrophy in phototrophic protists has emerged as a critical step in understanding marine food webs and cycling of materials in marine ecosystem. To investigate the feeding of newly described mixotrophic dinoflagellate Ansanella granifera, we explored the feeding mechanism and the different types of species that A. granifera was able to feed on. In addition, we measured the growth and ingestion rates of A. granifera feeding on the prasinophyte Pyramimonas sp., the only algal prey, as a function of prey concentration. A. granifera was able to feed on heterotrophic bacteria and the cyanobacterium Synechococcus sp. However, among the 12 species of algal prey offered, A. granifera ingested only Pyramimonas sp. A. granifera ingested the algal prey cell by engulfment. With increasing mean prey concentration, the growth rate of A. granifera feeding on Pyramimonas sp. increased rapidly, but became saturated at a concentration of $434ngCmL^{-1}$ (10,845 cells $mL^{-1}$). The maximum specific growth rate (i.e., mixotrophic growth) of A. granifera feeding on Pyramimonas sp. was $1.426d^{-1}$, at $20^{\circ}C$ under a 14 : 10 h light-dark cycle of $20{\mu}Em^{-2}s^{-1}$, while the growth rate (i.e., phototrophic growth) under similar light conditions without added prey was $0.391d^{-1}$. With increasing mean prey concentration, the ingestion rate of A. granifera feeding on Pyramimonas sp. increased rapidly, but slightly at the concentrations ${\geq}306ngCmL^{-1}$ (7,649 cells $mL^{-1}$). The maximum ingestion rate of A. granifera feeding on Pyramimonas sp. was 0.97 ng C $predator^{-1}d^{-1}$ (24.3 cells $grazer^{-1}d^{-1}$). The calculated grazing coefficients for A. granifera feeding on co-occurring Pyramimonas sp. were up to $2.78d^{-1}$. The results of the present study suggest that A. granifera can sometimes have a considerable grazing impact on the population of Pyramimonas spp.