• ALGAE
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• v.23 no.1
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• pp.83-90
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• 2008

Eelgrass beds are very productive and provide nursery functions for a variety of fish and shellfish species. Management for the conservation of eelgrass beds along the Korean coasts is critical, and requires comprehensive strategies such as vegetation mapping. We suggest a mapping method to spatial distribution and quantify of eelgrass beds using a digital echosounder. Echosounding data were collected from the northeast part of Kwangyang Bay, on the south of Korea, in March, 2007. A transducer was attached to a boat equipped with a DGPS. The boat completed a transect survey scanning whole eelgrass beds of 11.7 km2 with a speed of 1.5-2 m s-1 (3-4 knot). The acoustic reflectivity of eelgrass allowed for detection and explicit measurements of canopy cover and height. The results showed that eelgrass bed was distributed in depth from 1.19 to 3.6 m (below MSL) and total dry weight biomass of 4.1 ton with a vegetation area of 4.05 km2. This technique was found to be an effective way to undertake the patch size and biomass of eelgrass over large areas as nondestructive sampling.

• Ocean and Polar Research
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• v.24 no.1
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• pp.55-61
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• 2002

Eelgrass, Zostera marina L. widely spreads throughout all the coastal areas of the Korean Peninsula. However, some previously reported eelgrass populations disappeared. The disappearance was probably caused by anthropogenic disturbance such as reclamation and pollutant or exceeded nutrient release. Eelgrass beds occurred from the intertidal to the subtidal zone, mainly in lagoon, estuaries, ports, barrier reef and bays. Eelgrass beds were also found at the intertidal mud and sand flats, subtidal mud and sandbank in more exposed areas. Habitat characteristics of eelgrass beds distributed on the coasts of the Korean Peninsula varied among coast areas. Eelgrass distributed constantly throughout the southern coast of Korea, while the distribution was limited at lagoon, bay, port, or barrier reef on the eastern coast, because of steep water depth and high wave energy in that coast. On the western coast, eelgrass mainly appeared at the intertidal and subtidal zones in islands. Sediment characteristics of the Z. marina beds varied with locality, tidal current and water motion. Sediments of Z. marina beds were composed of sand, muddy sand, sandy mud and mud. Mean grain size ranged from 1.5 to 4.1 phi.

• Economic and Environmental Geology
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• v.12 no.1
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• pp.1-12
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• 1979

A model study was conducted for the interpretation of simple geologic structures. Experiments were carried out for the cases of two horizontal beds and dipping beds in a water tank by using Wenner and Schlumberger arrays respectively. As a geologic stratum of experimental model, cement be (cement: sand=1:2) of $70cm{\times}60cm{\times}10cm$ was used. It was found out from a preliminary experiment that a measuring sounding of Wenner arrays is one third of the distance between two current electrodes, and Schlumberger arrays is one fourth of the distance which is a half of the value determined by usual method of calculation. Equi-resistivity curves were obtained for the cases of horizontal beds and dipping beds, and mapped on the longitudinal and cross sections of the water tank. These curves delineate the shape and degree of dip of bed to some extent. The calculation of depth to beds by using a master curve is somewhat complicated and inexact. In this study, new method for this calculation using a ${\rho}_a/{\rho}_1-a$ graph was proposed, and turned out that this method is simpler and exact.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1105-1117
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• 2023

In this study, the pressure drop behavior of single- and two-phase flows of air and water through the porous beds filled with uniform and non-uniform sized spherical particles was examined. The pressure drop data in the single-phase flow experiments for the uniform particle beds agreed well with the original Ergun correlation. The results from the two-phase flow experiments were analyzed using numerical results based on three types of previous models. In the experiments for the uniform particle beds, the data on the two-phase pressure drop clearly showed the effect of the flow regime transition with a variation in the gas flow rate under stagnant liquid condition. The numerical analyses indicated that the predictability of the previous models for the experimental data relied mainly on the sub-models of the flow regime transitions and interfacial drag. In the experiments for the non-uniform particle beds, the two-phase pressure loss could be predicted well with numerical calculations based on the effective particle diameter. However, the previous models failed to accurately predict the counter-current flooding limit observed in the experiments. Finally, we propose a relation of falling liquid velocity into the particle bed by gravity to appropriately simulate the CCFL phenomenon.

• Journal of Industrial Technology
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• v.1
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• pp.27-33
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• 1981

Due to intense tectonic activities and volcanic movements, coal mines exploration have been conflicted with problems so far. In this paper, computer calculation was specially applied for various model structures of inclined, anticlined and synclined coal beds. Of all these structures, the gradient of equipotential curves showed great as the dip of coal beds increases. Especially at synclined structure, the concaves appeared sharply in both sides of equipotential curves as the dip of coal beds increases. By above results, interpretation of coal exploration can be done by comparing field data one another.

• Geomechanics and Engineering
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• v.4 no.2
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• pp.79-90
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• 2012

Air pluviation method is widely adopted for preparation of large, uniform and repeatable sand beds of desired densities for laboratory studies to simulate in-situ conditions and obtain test results which are highly reliable. This paper presents details of a portable traveling pluviator recently developed for model sand bed preparation. The pluviator essentially consisted of a hopper, orifice plates for varying deposition intensity, combination of flexible and rigid tubes for smooth travel of material, and a set of diffuser sieves to obtain uniformity of pluviated sand bed. It was observed that sand beds of lower relative density can be achieved by controlling height of fall, whereas, denser sand beds could be obtained by controlling deposition intensity. Uniformity of pluviated sand beds was evaluated using cone penetration test and at lower relative densities minor variation in density was observed with depth. With increase in relative density of sand bed higher repeatability of uniform pluviation was achieved.

• Journal of the Korean earth science society
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• v.34 no.5
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• pp.381-392
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• 2013

Socheong island is a unique island containing Precambrian stromatolites in South Korea. Most of Socheong stromatolites are domes and columns, occurring as 10 cm to 1 m thick stromatolite beds. Lower parts of the stromatolite beds are predominantly composed of domes, but columns increase toward the upper level of stromatolite beds. In many of the stromatolite beds, inclined columns are easily identifiable, which is generally considered as a result of heliotropism. From general lithology, sedimentary structures, inclined angles and distributional pattern, and structural deformation of sedimentary rocks of Socheong island, the inclination of Socheong stromatolites could be better interpreted as a secondary structural deformation probably after formation of stromatolite columns, rather than as a result of heliotropism. However, at this moment, we do not clearly reject heliotropism interpretation for inclined columns of Socheong stromatolites. This is because the original position of stromatolite columns could have been lost if structural deformation had affected the whole sedimentary rocks of Socheong island.

• Kyungpook Mathematical Journal
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• v.61 no.2
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• pp.323-351
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• 2021

The present paper addresses magnetohydrodynamic pulsating flow and heat transfer of two immiscible, incompressible, and conducting couple stress fluids between two permeable beds. The flow between the permeable beds is assumed to be governed by Stokes' [28] couple stress fluid flow equations, whereas the dynamics of permeable beds is determined by Darcy's law. In this study, matching conditions were used at the fluid-fluid interface, whereas the B-J slip boundary condition was employed at the fluid-porous interface. The governing equations were solved analytically, and the expressions for velocity, temperature, mass flux, skin friction, and rate of heat transfer were obtained. The analytical expressions were numerically evaluated, and the results are presented through graphs and tables.

• Research in Community and Public Health Nursing
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• v.31 no.1
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• pp.1-12
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• 2020

Purpose: The purpose of this study was to identify the factors influencing organizational commitment of staffs according to the size of long-term care facility. Methods: A cross-sectional descriptive study was designed. Data collection was conducted for a total of 315 employees in long-term care facilities located in Seoul, Gyeonggi, Gangwon, Gyeongbuk, and Chungnam. Data were collected from July 2018 to October 2018 using questionnaires which included emotional labor, job satisfaction, organizational commitment, and general characteristics. In order to confirm the differences in the size of the facility, the facilities with less than 30 beds, those with 30-99 beds, and those with more than 100 beds were analyzed. Data were analyzed using descriptive statistics, t-test, ANOVA, Mann-Whitney U test, Kruskal-Wallis H test, Pearson's correlation analysis, and multiple regression. Results: The job satisfaction and organizational commitment were significantly different according to the size of long-term care facility. Organizational commitment was influenced by 'external job satisfaction' in less than 30 beds, was influenced by 'external job satisfaction, and attentiveness to required display rules of emotional labor' in 30~99 beds, and then was influenced by 'type of job, and internal job satisfaction' in more than 100 beds. The predict variables accounted for 23.0%, 41.0%, and 34.0% of organizational commitment respectively. Conclusion: These findings show that tailored interventions should be provided depending on the size of facility in order to increase organizational commitment. In addition, organizational commitment programs should be developed by considering strategies to reduce the emotional labor and to increase job satisfaction.

• Journal of the Korea Furniture Society
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• v.22 no.1
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• pp.72-81
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• 2011

These days, beds have been developed not as furniture to sleep in but Healthcare Furniture. The function of heating, non-electronic-waves and far-infrared rays have been added. Also, eco-friendly materials such as stone, mud, rubber and wood are combined to them together with the radiation-heating method using heat conduction through electronic coil and hot water circulation. Modern people suffer from stress and fatigue. The hot issue is "health." Focused on the health, the development of design for beds considering the influence electronic waves, anions, deep sleep and the density of toxic materials have on human bodies has become urgent. In this study, the trend, specification and efficiency of the functional health-related electronic coil technology are analyzed. Through the analysis, the environmental standards are set. According to them, technology, eco-friendly materials and additional functions for the development of the design are considered. Also, the government is promoting the IEC international standardization for the Korean traditional floor heating style beds. In preparation for that, we adopted new HPT method technology. It enables non-electronic-waves, low electricity and stable temperature maintenance control for the warm top and the cool bottom. Also, the head boards and the frames of the beds can be separated. Through this separation, the beds can be easily moved or installed. Eco-friendly materials such as Hinoki cypress wood and red clay and the existing tables function are combined to the head boards so they can be used as drawers and display shelves. If they are used as separate items, they can be used as covers. This is how we suggest the design for the heating beds.