• Textile Coloration and Finishing
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• v.9 no.6
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• pp.10-17
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• 1997

In order to improve the anti-static property of several hydrophobic fibers by sputter etching, polyester, polypropylene and poly(p-phenylene sulfide) have been etched by sputtering in the presence of argon gas and the resulting anti-static property investigated by half time decay, the time of water permeation, weight loss rate and scanning electron microscope(SEM). The temporary change and durability of anti-static property of samples treated with sputter etching were evaluated. The results were as follows; 1) Half time decay of samples treated with sputter etching were decreased about 18~38%. According to increasing sputter etching time, half time decay is decreased. 2) The wettability and weight loss rate of treated samples were increased remarkably. According to the SEM photographs, many microcraters on the substrate surface by the sputter etching were observed. 3) Although the washing treatment and the time elapsed after treatment are allowed longer, the variation of half time decay hardly can find.

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.83-92
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• 2016

Objective: This study aimed to compare differences in biomechanical factors according to distance changes in relation to approaches during a round of golf to obtain basic data on golf swings. Methods: The research subjects were 8 KPGA-affiliated professional golfers who performed approach shots that put a ball into a circle of 8 feet in diameter from distances of 30, 50, and 70 m. Data were collected by using six infrared cameras and a ground reaction force device, which were applied to calculate biomechanical factors by using Kwon3D XP. The calculated data were subjected to one-way ANOVA by using SPSS 20.0, with the significance level set at p value of 0.05. Results: Elapsed time, stance width, clubhead position variation, clubhead synthesis speed, and cocking angle significantly differed according to distance change during the approach swing. Clubhead speed was positively related with stance width and clubhead displacement. Ground reaction force significantly differed according to distance change during the approach swing. Factors before and after showed differences in other states, except in the impact state. Conclusion: In the present study, we drew several conclusions regarding biomechanical factors and ground reaction forces according to distance change in the approach swing of professional golfers. According to these conclusions, we suggest that distance control with swing range is more important than power control in maintaining the accuracy and consistency of golf swing and is the most important mechanism of golf swing.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.117-128
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• 2000

The present study explored the influence of temporomandibular disorders(TMD) with anterior open bite on swallowing. Fifteen subjects with anterior open bite(group A), 9 subjects with anterior open bite and TMD(group B), and 24 subjects without malocclusion or TMD symptoms (group C) were included. BioPAK system(Bioresearch Inc., Milwaukee, WI, USA) was used to record the muscle activities of anterior temporal, masseter, sternocleidomastoid(SCM) and anterior digastric muscles during maximum clenching and swallowing. Positional change of the mandible during swallowing was also recorded using the same system. The obtained results were as follows: 1. Group A, B, and C did not show significant differences each other in the muscle activity of resting position in most of head and neck muscles. 2. Group B showed significantly lower muscle activity in maximum clenching than group C in anterior temporal(p<0.01), masseter(p<0.05), SCM(p<0.05) and digastric muscles(p<0.05). 3. Group A showed significantly lower muscle activity during swallowing than group C in anterior temporal and masseter muscles(p<0.01). Group B showed significantly lower muscle activity during swallowing than group C in anterior temporal(p<0.01), masseter(p<0.01), and SCM muscles(p<0.05). 4. Group A and B showed increased positional change of the mandible during swallowing measured from vertical, anteroposterior and lateral aspects, and prolonged swallowing(p<0.05). 5. After given instructions for normal swallowing pattern, group A and B showed increased muscle activity during swallowing in anterior temporal, masseter and SCM muscles(p<0.01). Positional change of the mandible and time elapsed for swallowing also decreased after the instruction(p<0.01). 6. Occlusal splint did not change the muscle activity during swallowing. However, vertical change(p<0.01) and swallowing time(p<0.05) were decreased with splint.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.1101-1105
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• 1989

Fifty one patients with empyema thoracic were managed at the Kyung Hee University Medical Center during 5 years between December, 1982, and December, 1987. The patients were classified into two groups; group A [early minithoracotomy-9 patients] and group B[conventional chest tube insertion-42 patients]. Each group was retrospectively analyzed to compare the results in terms of leukocyte count change, body temperature change, duration of hospitalization, elapsed time to chest tube removal and the need for subsequent decortication and tube change. There was no statistical difference between two groups in terms of etiology, age and sex. l. In the group A, mean preoperative leukocyte count [19,300/mme] decreased to 8,688/mme postoperatively. In the group B, leukocyte count changed from 16,985/mme to 14,433/mme. Their differences were significant [P< 0.05]. 2. In the group A, mean preoperative body temperature [38.5] decreased to 36.7. In the group B, body temperature changed from 38.1oC to 37.5 oC. Their differences were significant [P < 0.05]. 3. Mean duration of Hospitalization; 18.2 days [group A], 30.2 days [group B]. Their differences were significant [P < 0.01]. 4. Mean elapsing time for chest tube removal; 15.2 days [group A], 28.5 days [group B]. Their differences were significant [P < 0.01]. 5. There was no need for subsequent decortication and chest tube change in the group A. There were 22 cases [52.3 %] for subsequent decortication and 12 cases [28.6 %] for chest tube change in the group B. Early minithoracotomy in treating empyema thoracis resulted in a shorter hospital stay and a shorter period of tube drainage than conventional method.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.324-329
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• 2008

The liquid cooling effect of a natural convection type radiator by using the PCM has been investigated experimentally. The radiator size is $423{\times}295{\times}83$ mm and PCM container size is $398{\times}270{\times}26$ mm. The objective is elapsed time higher than maximum time to reach for maximum operating temperature of a general liquid cooling radiator. This study, in order to study on the effects of the phase-change phenomenon, carried out the various mass flow rate, input electric power, ambient and melting point of three type PCM. For the above experimental parameter, the melting time was performed about 180/250/560 min at input power 150 W and ambient $30^{\circ}C$ from using the three type PCM(PCM_S1/S2/S3) respectively. Furthermore, the effects of the thermal dissipation was decreased higher input power than lower input power at heating block and melting time of PCM. However, the effects of mass flow rate did not nearly affect of the thermal performance especially.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.4
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• pp.1-10
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• 2023

As a result of climate change, non-point source pollution (NPS) from farmland with the steep slope during the rainy season is expected to have a significant impact on the water system. This study aimed to evaluate the effect of furrow mulching using alfalfa and PAM (Polyacrylamide) materials for each rainfall event, while considering the load characteristics of NPS. The study was conducted in Wanju-gun, Jeollabuk-do, in 2022, with a testbed that had a slope of 13%, sandy loam soil, and maize crops. The testbed was composed of four plots: bare soil (Bare), No mulching (Cont.), Vegetation mulching (VM), and PAM mulching (PM). Runoff was collected from each rainfall event using a 1/40 sampler and the NPS load was calculated by measuring the concentrations of SS, T-N, T-P, and TOC. During farming season, the reduction efficiency of NPS load was 37.1~59.5% for VM and 38.2~75.7% for PM. The analysis found that VM had a linear regression correlation (R²=0.28~0.86, P-value=0.01~0.1) with elapsed time of application, while PM had a quadratic regression correlation (R²=0.35~0.80, P-value=0.1). These results suggest that the selection of furrow mulch materials and the appropriate application method play a crucial role in reducing non-point pollution in farmland. Therefore, further studies on the time-series reduction effect based on the application method are recommended to develop more effective preemptive reduction technologies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.226-232
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• 1982

The measurements of the jerking force and the tail beat by hooked carp were carried out using a strain gauge at a fish pond from July to August 1981. The maximum jerking force was sustained for a while in the initial state after a carp was hooked, but the jerking force was gradually decreased as a function of the time elapsed until the fish was utterly exhausted, and it converged to the body weight at last. The results are as follows : 1. The maximum jerking force $F_m(g)$ can be expressed with empirical formula : $$F_m=3.23W+105$$ where W (g) is the body weight. 2. Dynamic change of the maximum jerking force $F_n(g)$ by one tail beat with time $t_{n}(-10T/2{\leq}\;t_n{\leq}10T/2)$ can he induced with the equation as follows : $$F_n=(0.27W-6.52)(|t_n|+C)^{-2.10}$$ where the period T (sec) is given by the following equation with the body weight : T=0.000385W+0.193 3. The jerking force at each of the peak points $F_p$ (g) varies with the time elapsed t (sec) as following equation : $$F_{p}=(2.23W+105)e^{-{\beta}t}+W$$. The value of durability index $\beta$ was nearly zero in the initial state and about 1.7 in the exhausted state at last. 4. It was clearly shown that the change of jerking force by hooked carp was closely related to the tail beat from a paired difference T-test.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.330-335
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• 2005

This study was performed for the analysis of the variation characteristics on riverbed according to the arrangement of stream. It was monitored of the variation progress of riverbed dependent on the elapsed time after the arrangement and It was studied that the hydraulic adjustment of the riverbed caused by the variation of the riverbed. The large amount of deposit just after the construction in which the riverbed was arranged to natural form was come from the reduction of flow rate by the installed artificialities such as weirs and stone weirs and by the stones or the concrete blocks attached to the stream sides of riverbanks. This phenomenon was well consistent with the usual characteristics that the accumulation is induced on upper stream of hydraulic artificialities and the erosion is induced on down stream of hydraulic artificialities. The large reduction of the deposit 1 year later after the construction showed that the riverbed eroded considerably because of the recovery of flow amount and the rise of flow rate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.293-297
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• 1998

The influence of ion implantation on surface properties of polymers was studied. We investigated microhardness, friction, wear and wettablility of polyimide. Energies of 50, 200keV were used with doses range from $1{\times}10^{13} to 1{\times}10^{16} [ions/cm^2]$. The implanted ion species were B, N and Ar. The microhardness of polyimide was increased after implantation for doses of $1{\times}10^{15}\; [ions/cm^2]$. A reduction of the friction coefficient was in most case correlated with a reduction of wear. The contact angles of water for $B^+,N^+$ implanted polyimide decreased from $76^{\circ}C$ to zero, as the fluencies increased at energies of 50 and 200 KeV. However, the contact angle of Ar ion implanted polyimide did not change under ambient room conditions even if the time elapsed. SEM measurement was performed to characterize the modified surface layer.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.437-439
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• 2007

This paper was analyzed the resistivity change characteristic of mortar model block and concrete that was made earth electrode that's used concrete or basic concrete of building for 1 year. The early resistivity measurement value of concrete model block is higher than mortar model block. But after 1 year the resistivity measurement value of mortar model block is significantly higher than concrete model block. Because depends on time elapsed complete dryness factor of mortar model block that has not gravel is higher than concrete model block. And absorptance and function of mortar mode block was by far outstanding than concrete model block in the data for verification of the amount of contained water and the amount of dryness of mortar model block and concrete model block.