• Journal of the Korean Ceramic Society
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• v.35 no.2
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• pp.163-171
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• 1998

Continuously contacting with camshaft the face of Valve Lifter made of cast iron brings about abnormal wear such as unfairwear or earlywear because it is heavily loaded in the valve train systems as the engine gets more powered. This abnormal wear becomes a defet namely over-clearance when the valve is lifting so that the fuel gas imperfectly combusted by unsuitable open or close aaction of the engine valve in the combustion chamber. The imperfect combustion in the end results in the major cause of air pollution and combustion chamber. The imperfectly combusted by unsuitable open or close action of the engine valve in the combustion chamber. The imperfect combustion in the end results in the major causes of air pollution and decrease of the engine output. Consequently to prevent this wear this study was to develop the valve lifter which is joined by brazing process with SCM435H and a tip by manufacturing the face as a superhardened which is joined by brazing process with SCM435H and a tip by manufacturing the face as a superhardened ceramics alloy which has high wear resistance. Having the excellent surface hardness with Hv1100-1200 the sintered body developed with superhardened alloy(WC) can endure the severe face loading in the valve train system. We experienced with various brazing alloys and obtained the excellent joining strength to the joint had 150MPa shear strength. Interface analysis and microstructure in a joint were examined through SEM & EDS Optical microscope. Also 2,500 hours high speed(3,000-4,000 rpm) and continuous (1step 12hr) engine dynamo testing was carried out to casting valve liter and ceramics-metal joint valve lifter so that the abnormal wears were compared and evaluated.

• Journal of Preventive Medicine and Public Health
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• v.35 no.3
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• pp.263-268
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• 2002

Objective : This study was aiming at estimating the joint effects of various risk factors associated with uterine cervix cancer in Korea. Methods : Data obtained from a case-control study were analyzed with a multiplicative model. Results : After adjustment for age and husband's educational attainments, the family history of cervical cancer (OR=2.1, 95% CI=1.2-3.9), unstable marital status due to separation, by death or divorce, etc. (OR=2.8, 95% CI=1.7-4.6), and a large number of deliveries ($\geq$3 vs. nulliparous OR=6.5, 55% CI=1.4-29.0) increased the risk of uterine cervix cancer, Conversely, first sexual intercourse at an older age ($\geq$25 years vs. <19 years OR=0.4, 95% CI=0.2-0.6) and husband's circumcision (OR=0.7, 95% CI=0.5-1.0) decreased the risk. In the multiplicative model, the highest joint risk (OR=39.2, 95% CI 5.9-258.9) was observed in women with a family history of uterine cervical cancer, an unstable marital status, where the ex-husband was not circumcised, with 3 or more delivery experiences, and having her first sexual intercourse when younger than 19 years of age. However, women without a family history of uterine cervix cancer, married to a circumcised husband, having had her first sexual intercourse at 25 years or older, and nulliparous, showed the lowest joint effect (OR=0.3, 95% CI=0.1-0.5). Conclusion : As carcinogenesis is a complex action involving various factors, we consider a joint effects approach to be appropriate in an epidemiological study on risk factors for uterine cervix neoplasms cervix neoplasm.

• PNF and Movement
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• v.19 no.1
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• pp.147-152
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• 2021

Purpose: This study was conducted to investigate the functional differences of the two heads of the biceps brachii by measuring the functions in supination according to pronation by the angle of the flexion of the elbow joint, except for the activities of the elbow flexors. Methods: This study was conducted with 25 healthy men in their 20s. At a glenohumeral-joint 0˚ flexion posture, angles of flexion of the elbow joint of 0˚, 30˚, 60˚, 90˚, and 120˚ were randomly provided, and they were asked to perform supination and pronation with an elastic band. Using an eight-channel surface electromyogram, the muscle activities of the long and short heads of the biceps brachii were measured. The activities of the short and long heads according to the angle were analyzed using a one-way ANOVA, and as a post-test, LSD was employed. Results: The analysis of the impact of the resistance of the elastic band in supination on the differences in the muscle activities in the short and long heads suggests there was a significant difference between 0˚ and 30˚ (p < 0.05). Conclusion: In supination according to forearm pronation, the long head had greater action in the early flexion posture of the elbow joint, and it is judged that the ratio of the flexion of the elbow joint according to the actions of the biceps brachii was considered small.

• Earthquakes and Structures
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• v.21 no.6
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• pp.613-625
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• 2021

Non-seismically designed eccentric reinforced concrete beam-column joints were extensively used in existing reinforced concrete frame buildings, which were found to be vulnerable to seismic action in many incidences. To provide a fundamental understanding of the seismic performance and failure mechanism of the joints, three 2/3-scale exterior beam-column joints with non-seismically designed details were cast and tested under reversed cyclic loads simulating earthquake excitation. In this investigation, particular emphasis was given on the effects of the eccentricity between the centerlines of the beam and the column. It is shown that the eccentricity had significant effects on the damage characteristics, shear strength, and displacement ductility of the specimens. In addition, shear deformation and the strain of joint hoops were found to concentrate on the eccentric face of the joint. The results demonstrated that the specimen with an eccentricity of 1/4 column width failed in a brittle manner with premature joint shear failure, while the other specimens with less or no eccentricity failed in a ductile manner with joint shear failure after beam flexural yielding. Test results are compared with those predicted by three seismic design codes and two non-seismic design codes. In general, the codes do not accurately predict the shear strength of the eccentric joints with non-seismic details.

• Magazine of the Korea Concrete Institute
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• v.6 no.1
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• pp.111-119
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• 1994

The strength of vertical joints of precast concrete large panel structures depends on the many factors, such as the bond strength of grout concrete (or mortar), the interlocking of the shear keys, the dowel action of horizontal bars. Many experimental studies have been conducted to in vestigate the shear strength of the vertical joints. In domestic, a few design formulas to predict shear strength of the vertical joint were proposed by some investigators, but formulas were based on limited experimental results. The objective of this paper is to propose a suitable formula for the shear strength of vertical joints with 94 vertical joints experimental data using the modified Mohr-Coulomb's 4ield theory and regression analysis. From the comparison of the proposed formula with others, it is shown that the proposed formula can be used economically for the design of vertical joints.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.851-859
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• 2011

In this paper, we propose the method that automatically extracts the silhouette and the joints of consecutive input image, and track joints to trace object for interaction between human and computer. Also the proposed method presents the action of human being to map human body using joints. To implement the algorithm, we model human body using 14 joints to refer to body size. The proposed method converts RGB color image acquired through a single camera to hue, saturation, value images and extracts body's silhouette using the difference between the background and input. Then we automatically extracts joints using the corner points of the extracted silhouette and the data of body's model. The motion of object is tracted by applying block-matching method to areas around joints among all image and the human's motion is mapped using positions of joints. The proposed method is applied to the test videos and the result shows that the proposed method automatically extracts joints and effectively maps human body by the detected joints. Also the human's action is aptly expressed to reflect locations of the joints

• Korean journal of applied entomology
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• v.36 no.1
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• pp.105-110
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• 1997

Mixture study of bifenthrin and prothiofos was conducted to control insecticide resistant diamondback moth (DBM), Plutella xylostella, which had shown 581, 18, 19, 11 fold resistance to fenvalerate, cypermethrin, furathiocarb, and prothiofos in Chinju strain, respectively and 38 and 9 fold resistance to fenvalerate and furathiocarb in Seosang strain, respectively. Optimal mixture ratios of bifenthrin and prothiofos was selected against Seosang strain of DBM by leaf dipping method in laboratory and by field test. Maximum co-toxicity coefficient by dipping method was shown at a ratio of 1:50 mixture of bifenthrin 1EC and prothiofos 50EC in active ingredient(a.i.) by 243.2 and then suddenly decreased. The mixed formulation from the dipping test was examined at the cabbage field of Seosang, Hamyang. Although insecticides were reduced to half, control efficacy was similar to farmer's conventional method. In addition, the mixture combination was also more effective against Chinju DBM population which had very high level of resistance to several representative insecticides. Mixture methods of insecticides will be effective countermeasures to the resistance problem of pests.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.433-445
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• 2009

The panels are used as a composite part of the completed deck. They replace the main bottom transverse deck reinforcement and also serve as a form surface for the cast-in-place concrete upper layer that contains the top of deck reinforcement. Research has also demonstrated that mechanical shear ties on the top of the panels are required. In a composite deck with precast panels, it is required to notice behavior of transverse joints between panels. In this paper, static tests of composite deck with shear ties and loop joints were conducted. From the results, the validity of loop joints for continuity of deck was observed. Also, a composite behavior was abserved between precast panel and slab concrete. Tested composite decks with shear ties have 140~164% ultimate strength than have no shear ties due to the increase of composite action. Therefore, the shear ties between the slabs were sufficient to enforce composite flexural behavior to failure.

• Physical Therapy Korea
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• v.5 no.4
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• pp.41-51
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• 1998

The right hip abductor musculature has been reported to demonstrate "stretch weakness" attributable to chronic elongation imposed by standing posture common to right-handed healthy persons. Kendall and associates have described the concept of "stretch weakness",. The purpose of this study was to assess isometric hip abduction torque and surface electromyographic activity (using MYOMED 432) in a sample of 40 healthy right-handed persons (20 male, 20 female), all of whom agreed to participate in the study, and compare side difference in the hip abductor musculature. In order to assure the statistical significance of the results, the paired t test was applied at the .05 level of significance. The results were as follows: 1) The difference in apparent leg length of right and left legs was significant at the .05 level. 2) There was a significant difference between right and left pelvic height (standing position) at the 05 level measurements, and scapula height at the .05 level. 3) Power measurements and action potentials of right hip abductor were greater than the left hip abductor regardless of the range of joint motion (inner range, outer range) 4) The difference in muscle power and action potentials according to inner or outer range of both hip abductor were significant at the .05 level. 5) In supine during active left hip abduction, the appearance of action potentials in the right hip abductors is indicative of contra-lateral effect (p<.05) These results suggest: In healthy right-handed persons, the apparent leg length on the right is longer than on the left, and pelvic height is elevated on the right side. Muscle those and muscle action potentials of the right hip abductor are higher than those of the left hip abductor in the lengthened position. Therefore, the results in this study are contrary to Kendall's. This type of study should be carried out in many physical therapy departments.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.1
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• pp.33-43
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• 2007

This study divided 35 hemiplegia patients into control group having standard physical therapy and gait training and functional electrical stimulation(FES) group using FES during gait training in order to examine the effects of applying FES to ankle joint dorsiflexor on motor unit action potential. Stimulation conditions of FES were pulse rate 35 pps, pulse width $250{\mu}s$, and on-time 0.3 second, treatment hour was 30 min. and treatment period was once a day for five days a week through six weeks. For functional evaluations before and after treatment, root mean square(RMS) were measured and the following conclusions were obtained. : In RMS analysis of motor unit action potential, gastrocnemius was significantly reduced in both weight bearing(p<.001) and bearing condition (p<.05). In conclusion, application of FES to hemiplegia patients in recovery stage during gait training decreased RMS and it was interpreted that it was caused by mitigation of muscular spasticity by reduction of motor unit.