• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.33-37
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• 1995

A side-cut grinding generates a machining error by the decrease of the quill rigidity. In this paper, The effect on the grinding force, machining error and surface roughness due to the change of the quill rigidity is investigated experimentally. The slenderness ratio of the quill is a significant factor to analyse the change of the grinding force and machining error.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.3
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• pp.841-847
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• 2016

To study the influence of background color and substratum on hypermelanosis of starry flounder, we compared the daily food intake (DFI), the feed efficiency (FE), the survival, the growth, the ratio of pigmented area on the blind side and the ratio of hypermelanic fish duplicately reared for 180 days in dark-green FRP aquarium (control), white FRP aquarium together with dark-green substratum. The ratio of pigmented area on the blind side was significantly higher at the dark-green group than at the white group. DFI, FE and growth were higher in the dark-green substratum. Pigmented area rate and ratio of hypermelanic fish were significantly higher at the dark green group than at the high dark-green substratum. The results suggest that bright tank color and substratum bottom could inhibit the hypermelanosis.

• The Journal of Korean Physical Therapy
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• v.13 no.1
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• pp.161-174
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• 2001

The purpose of this study was to reduce the spasticity of plantarflexion. the subjects of this study were 30 hemiplegic patients with stroke who received of physical therapy in JinJu o o hospital from May to July 2000. the subjects were divided into three groups(FES groups 10, FES + tilt table-wedge board standing groups 10, & tilt table-wedge board standing groups 10). The result were as follow 1. FES therapy was a effective method to reduce the spasticity of plantarflexor. there was a significant difference in modified Ashworth scale(p<.01). there was a significant difference in weight bearing ratio between nonparetic and paretic side(p<.01). 2. Tilt table-wedge board standing therapy was a effective method to reduce the spasticity of plantarflexor to a degree but there was a no significant difference in modified Ashworth scale(p<.05). there was a significant difference in weight bearing ratio between nonparetic and paretic side(p<.01). 3. Tilt table-wedge board standing therapy + FES therapy was a effective method to reduce the spasticity of plantarflexor. there was a significant difference in modified Ashworth scale(p<.01). there was a significant difference in weight bearing ratio between nonparetic and paretic side(p<.01) 4. There was a significant difference in weight bearing ratio between nonparetic and paretic side according to the grade spasticity(p<.01). 5. For normal persons vs hemiplegic patients, there was a significant different in weight bearing ratio between nonparetic and paretic side(experimental subjects 1 p<.01, experimental subjects 2 p<.01, control subjects p<.05).

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.14 no.4
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• pp.20-26
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• 2018

In this study, the performance characteristics of a welded plate heat exchanger was investigated experimentally. Performance tests were carried out according to the flow rate and inlet temperature of working fluid. As a result, the heat transfer capacity increased by 335.5 kW with an increasing the flow rate and temperature difference between hot and cold side. However, the overall heat transfer coefficient was increased with the increase of flow rate, and it was not effected significantly from inlet temperature difference between hot and cold working fluid. The pressure drop was increased by 55.78 kPa with an increasing the frow rate when the flow rate ratio between hot and cold side 1:1. However, the tendency of pressure drop was difference when flow rate ratio wasn't 1:1. In case that the flow rate ratio between hot and cold side was not 1:1, the pressure drop at the low flow rate side was higher than that when the flow rate ratio was 1:1, while pressure drop of the other side was decreased compared to that when the flow rate ratio was 1:1.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.215-223
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• 2000

In this study, the effect of stiffness ratio between base frame and anchorgae is evaluated and the seismic verification of nuclear power plant equipment anchorage is performed for typical equipment. The stiffness ratio between base frame and anchorage is mainly controlled by the effective height of side wall plate. And, the change of that stiffness ratio cause the large shift or ovreturning axis of equipment base. This shift of overturning axis of equipment base is able to reduce the factor of safety about 10%. Therefore, the adequate method for evaluating of effective height of side wall is required as further study.

• Journal of Sericultural and Entomological Science
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• v.13 no.2
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• pp.151-154
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• 1971

In the silkworm egg production, cutting of the cocoon's edge formed by silkworms forced to aid the emergence, and emergence is related to the amount of alkaloid liquid in the sucking stomach in certain varieties. In this study, there was no difference between cutting of portion and sex, and no significant between cutting of both sides and one side cocoons when comparing their emergence ratio. Expenditures and emergence ratio between both sides and one side cutting off must be studied in coming future.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.4 s.117
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• pp.105-115
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• 2006

Biotope Area Ratio ($BFF; BiotopFl{\"{a}}chenFaktor$) was developed in Berlin, Germany in 1990s and introduced to Korea in 1999. It is the ratio of the uncovered soil areas which have the natural circulating capability compared to whole development areas. This study seeks for alternative ways to increase Biotope Area Ratio of residential areas in the metropolitan areas of Korea by investigation on new housing developments. The study investigates four new towns including Seoul Eunpyung new town, Yongin Kusung district, Goyang Pungdong and Juyeopdong districts and Hwasung Dongtan district. The Biotope Area Ratio of study sites is between 23.51 % and 40.69%. This result is not relevant to land use conditions, such as the building-ta-land ratio, natural ground green area ratio. This ratio satisfies the minimum requirements of City of Seoul, except 2 sites. Considering that the study sites are relatively low density land use areas compared to Seoul's average, thus, a higher standards is necessary for new town housing complexes. Because Biotope Area Ratio includes artificial ground green area ratio, Biotope Area Ratio is possible can be increased with decreased natural ground green area ratio. And so, when Biotope Area Ratio is applied to new town development, it must go side by side with a definite natural ground green area ratio.

• Physical Therapy Korea
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• v.27 no.4
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• pp.241-249
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• 2020

Background: Prolonged standing during work causes a lower extremity pain and disorders. Patellofemoral pain syndrome (PFPS) is one of the common diagnoses of the knee pain. Although the etiology of PFPS is not completely understood, it is considered to be multifactorial. Objects: The purpose of this study was to investigate difference in strength of knee muscles, quadriceps:hamstring muscles strength ratio (Q:H ratio), asymmetry ratio of knee muscles strength and dorsiflexion range of motion (ROM) between standing workers with and without PFPS. Methods: Twenty-eight standing workers with PFPS and 26 age-, height-, and weight-matched standing workers without PFPS participated in this study. A tension sensor measured knee muscle strength, and motion sensor measured dorsiflexion ROM. The asymmetry ratio of knee muscles was calculated by a specific formula using the knee muscles strength of the dominant side and the sound side. An independent t-test was used to identify significant differences in the strength, ROM, Q:H ratio, and asymmetry ratio between the PFPS and normal groups. Results: The standing worker with PFPS have significantly lower dorsiflexion ROM (p < 0.000) and higher asymmetry ratio of the hamstring muscles strength (p < 0.000) compare to the standing worker without PFPS. No significant differences were seen in the strength of quadriceps muscle and hamstring muscles, Q:H ratio, and asymmetry ratio of quadriceps muscle strength. Conclusion: There was a significant difference in the asymmetry ratio of the isometric hamstring muscle strength. This finding suggests that the asymmetry ratio of isometric hamstring muscle strength may be more important than measuring only the hamstring muscle strength of the PFPS side. Furthermore, the results of this study showed a significant difference in dorsiflexion ROM between the standing industrial workers with and without PFPS. Dorsiflexion ROM and isometric hamstring muscle strength should be considered when evaluating the subjects with PFPS.

• Journal of Navigation and Port Research
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• v.45 no.3
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• pp.148-154
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• 2021

With advancements of quay side handling equipment and technologies, congestion in terminal operation has moved to the storage yard side from the quay side. The importance of storage yard management has increased in overall terminal operation. Thus, many studies have been conducted to optimize the storage yard management of container terminals. However, there is no academic work to estimate the change of storage yard occupancy ratio by itself in the future. This paper examines the probability of storage yard occupancy ratio in the container terminal of Busan New port using the Markov chain analysis which explains probability change with passing time. The result shows that it is most likely to have the probability of maintaining a high level of storage yard occupancy ratio in the container terminal of Busan New Port.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.77-80
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• 2006

Graft copolymerized polycarboxylate(PC)-type superplasticizers(PCs) which have carboxylic acid with $\pi$ bond among the molecular structure and polyethyleneglycol methyl ether methacrylate(PMEM) were synthesized by free radical reaction and investigated the chemical structure, polymerization condition, and physical and chemical properties. Also, the effects of PCs in the dispersion, adsorption and hydration of cement were evaluated. As the molecular weight of graft chain decreases, the adsorption amount on cement particles increased. It was advantageous for the flow to reduce molar ratio, the lower the side bone molecular weight, and increase the molar ratio, the larger the side bone molecular weight. The hydration reaction speed was highly delayed at day 1, due to increase in molar ratio and reduction in side bone molecular weight, but it was recovered in the days after.