• ALGAE
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• v.37 no.1
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• pp.49-62
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• 2022

Water temperature affects plankton survival and growth. The dinoflagellate Shimiella gracilenta survives using the plastids of ingested prey, indicating kleptoplastidy. However, studies on the effects of water temperature on kleptoplastidic dinoflagellates are lacking. We explored the growth and ingestion rates of S. gracilenta as a function of water temperature. Furthermore, using data on its spatiotemporal distribution in Korean coastal waters during 2015-2018, we predicted its distribution under elevated temperature conditions of +2, +4, and +6℃. Growth rates of S. gracilenta with and without Teleaulax amphioxeia prey as well as ingestion rates were significantly affected by water temperature. Growth rates of S. gracilenta with and without prey were positive or zero at 5-25℃ but were negative at ≥30℃. The maximum growth rate of S. gracilenta with T. amphioxeia was 0.85 d^-1, achieved at 25℃, and 0.21 d^-1 at 20℃ without prey. The ingestion rate of S. gracilenta on T. amphioxeia at 25℃ (0.05 ng C predator^-1 d^-1) was greater than that at 20℃ (0.04 ng C predator^-1 d^-1). Thus, feeding may shift the optimal temperature for the maximum growth rate of S. gracilenta from 20 to 25℃. In spring and winter, the distributions of S. gracilenta under elevated temperature conditions were predicted not to differ from those during 2015-2018. However, S. gracilenta was predicted not to survive at some additional stations under elevated temperature conditions of +2, +4, and +6℃ in summer or under elevated temperature conditions of +6℃ in autumn. Therefore, global warming may affect the distribution of S. gracilenta.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1429-1435
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• 2021

The temperature distribution of an electromagnetic pump was analyzed with a flow rate of 1380 L/min and a pressure of 4 bar designed for the sodium thermo-hydraulic test in the Sodium Test Loop for Safety Simulation and Assessment-Phase 1 (STELLA-1). The electromagnetic pump was used for the circulation of the liquid sodium coolant in the Intermediate Heat Transport System (IHTS) of the Prototype Gen-IV Sodium-cooled Fast Reactor (PGSFR) with an electric power of 150 MWe. The temperature distribution of the components of the electromagnetic pump was numerically analyzed to prevent functional degradation in the high temperature environment during pump operation. The heat transfer was numerically calculated using ANSYS Fluent for prediction of the temperature distribution in the excited coils, the electromagnet core, and the liquid sodium flow channel of the electromagnetic pump. The temperature distribution of operating electromagnetic pump was compared with cooling of natural and forced air circulation. The temperature in the coil, the core and the flow gap in the two conditions, natural circulation and forced circulation, were compared. The electromagnetic pump with cooling of forced circulation had better efficiency than natural circulation even considering consumption of the input power for the air blower. Accordingly, this study judged that forced cooling is good for both maintenance and efficiency of the electromagnetic pump.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.1
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• pp.16-26
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• 1997

China is one of the few countries where natural disaster strike frequently and cause heavy damage. In this paper, we mathematically develop two models to assess fuzzy risk of natural disaster in China. One is to assess the risk based on database of historical disaster effects by using information diffusion method relevant in fuzzy information analysis. In another model, we give an overview over advanced method to calculate the risk of release, exposure and consequence assessent, where information distribution technique is used to calculate basic fuzzy relationships showing historical experience of natural disasters, and fuzzy approximate inference is employed to study loss risk based on these basic relationships. We also present an examples to show how to use the first model. Result show that the model is effective for natural disaster risk assessment.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.4
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• pp.347-354
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• 2005

This paper compared vertical temperature distribution between the existing balcony model without ventilator facilities and the improved balcony model with ventilator facilities using differential equation. As the air inside of balcony is heated by solar radiation this heated air is not exhausted in the existing balcony, remaining stagnant. The air temperature distribution was $26.7{\sim}29.3^{\circ}C$ in balcony without natural ventilator system. This heated air affected the rising air temperature of adjacent spaces such as living room and bedroom in the existing balcony. But, as the heated air inside of the improved balcony model is exhausted through natural ventilator facilities in summer, the air temperature in balcony has fallen. The air temperature distribution in improved balcony was $24.8{\sim}26.7^{\circ}C$ for the inlet air speed of 1 m/s and $24.6{\sim}26.7^{\circ}C$ for the inlet air speed of 3 m/s. The energy consumption of the improved balcony is 2.5 times less than of the existing balcony. The improved balcony with the closed damper makes a roll as the existing balcony in the aspect of the heating effect. When the heated air in the improved balcony is supplied, the air temperature is raised and the ventilation effect in adjacent spaces was improved.

• Steel and Composite Structures
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• v.49 no.6
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• pp.713-728
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• 2023

This paper aims to investigate the free vibration analysis of FG plates, taking into account the effects of even and uneven porosity. The study employs the Hellinger-Reisner functional and obtains the element's bending stress and membrane stress fields from the analytical solution of the governing equations of the thick plate and plane problem, respectively. The displacement field serves as the second independent field. While few articles on free vibration analysis of circular plates exist, this paper investigates the free vibration of both rectangular and circular plates. After validating the proposed element, the paper investigates the effects of porosity distributions on the natural frequency of the FG porous plate. The study calculates the natural frequency of thin and thick bending plates with different aspect ratios and support conditions for various porosity and volume fraction index values. The study uses three types of porosity distributions, X, V, and O, for the uneven porosity distribution case. For O and V porosity distribution modes, porosity has a minor effect on the natural frequency for both circular and rectangular plates. However, in the case of even porosity distribution or X porosity distribution, the effect of porosity on the natural frequency of circular and rectangular plates increases with an increase in the volume fraction index.

• Ecology and Resilient Infrastructure
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• v.4 no.2
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• pp.115-121
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• 2017

This study estimated potential natural vegetation in Gayasan National Park through the occurrence probability distribution by using geographic information system (GIS). in Gayasan National Park. Correlation and factor analysis were analyzed to estimate probability distribution. The presence of the Gaya National Park Vegetation survey results showed that 128 communities were distributed. The analyzed relationship between actual vegetation and distribution factors such as elevation, aspect, slope, topographic index, annual mean temperature, warmth index and potential evapotranspiration in Gayasan national park. The probability distribution of potential natural vegetation communities at least 0.3 odds were the advent of Pinus densiflora communities with the highest 55.80%, Quercus mongolica community is 44.05%, 0.09% is Quercus acutissima communities, Quercus variabilis communities are found to be 0.06%. If you want to limit the factors that affect the distribution of vegetation by factors presented in this study, the potential natural vegetation of the Gaya National Park was expected to appear in Quercus mongolica community (43.1%) and Pinus densiflora communities (56.9%).

• Korean Journal of Plant Resources
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• v.28 no.4
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• pp.400-410
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• 2015

Juniperus chinensis (Cupressaceae) is a valuable woody plant resource, but this rare plant is only distributed in restricted regions in Korea. In this study, we surveyed the geographic distribution regions, variation of sex ratio and the dynamics of natural populations of J. chinensis. in order to establish conservation strategies for the sustainable conservation of this important resource tree. The 17 natural populations of J. chinensis are restrictively distributed in the shore cliffs of (1) Ulleungdo island, (2) Gyeongju-si to Gangneung-si of the eastern coast, the riverside cliff along (3) Donggang-river of Jungsun-gun and Pyeongchang-gun and (4) branch of Nakdonggang-river in Uiseong-gun. The populations in Ulleungdo island showed continuous population distribution of over 200 individuals, but populations in other regions had discontinuous population distribution of under 200. The population of J. chinensis surveyed in Korea was estimated in ca. 3,200 individuals. The sex ratio (male/female) among populations of J. chinensis was diverse with variation from 0.46~1.67 range, but showed no significance. The sex ratio of the total individuals by species level was 0.74, and the percentage of female tree was significantly higher than the male. The results of dynamics analysis within population among regions showed that seedlings and saplings of J. chinensis in three regions surveyed were continuously regenerating. The distribution of DBH class showed a stable population structure of inverse J shape graph, but fragmentation and decrease in populations because of invading broad-leaved shrubs and trees from the surroundings were concerned. Further studies, and in situ and ex situ conservation strategies for the sustainable conservation on natural populations of this rare resources woody plant, J. chinensis in Korea are recommended.

• East Asian mathematical journal
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• v.38 no.4
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• pp.379-396
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• 2022

In this paper, we investigate distribution strategies in the Egyptian fraction, and through this, we examine the distribution strategies of (fraction)÷(fraction) and then provide some educational implications. The (natural number)÷(natural number) of the sharing situation has the meaning of 'share' per unit, which can be seen as a situation where the unit ratio is determined. These concepts can also naturally be extended to the case of (fraction)÷(fraction) by some problem posing situations. That is to say, the case of (fraction)÷(fraction) can be deduced the case (natural number)÷(natural number) by the re-statement of the problem.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.534-539
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• 1996

Total 276 soil actinomycete strains were isolated from 46 soil samples collected at domestic natural caves; the Kosu, Chundong, and Nodong caves at Chungbook province, the Kossi cave at Kangwon province, the Sungruye cave at Kyungbook province, the Hyupjae, Ssangyong, and Manjang caves at Cheju province. All of these isolates were identified to the genus level based on morphological and physiological characteristics. As the result, 52.5% of those isolates were Streptomyces, 16.3% were Micromonospora, 22.8% were Nocardioform group, 1.1% were Actinomadura, 0.3% were Nocardiopsis, 0.3% were Streptosporangium, 0.3% were Nocardioides, 1.4% were Kineosporia, 4.7% were the others. Streptomycete strains were the most abundant, but were relatively less comparing to general distribution pattern. Nocardioform and Micromonospora strains were quite abundant, and other rare actinomycete groups were somewhat abundant comparing to general distribution pattern previously reported. Especially Nocardioform strains were highly abundant at almost of the natural caves.

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.191-204
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• 2006

This paper investigate the optimum thickness distribution of plate structure with different essential boundary conditions in the fundamental natural frequency maximization problem. In this study, the fundamental natural frequency is considered as the objective function to be maximized and the initial volume of structures is used as the constraint function. The computer-aided geometric design (CAGD) such as Coon's patch representation is used to represent the thickness distribution of plates. A reliable degenerated shell finite element is adopted calculate the accurate fundamental natural frequency of the plates. Robust optimization algorithms implemented in the optimizer DoT are adopted to search optimum thickness values during the optimization iteration. Finally, the optimum thickness distribution with respect to different boundary condition