• Science of Emotion and Sensibility
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• v.13 no.1
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• pp.207-214
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• 2010

The aim of this study was to investigate upper and lower limb muscle activity using EMG(electromyogram) sensors while walking and identify normal gait pattern using FSR(force sensing resistor) sensor. Fifteen college students participated in this study and their EMG and FSR signal were measured during stopping and walking trials. EMG signals from upper(pectoralis major and trapezius) and lower limbs(rectus femoris, biceps femoris, vastus medialis, vastus lateralis, semimembranosus, semitendinosus, soleus, peroneus longus, gastrocnemius medialis, and gastrocnemius lateralis) were obtained using the surface electrodes. FSR measured pressures on 8 areas of the sole of the foot during walking. EMG results showed that all muscle activities except for vastus lateralis and semimembranosus during walking had higher amplitudes than stopping. Additionally, muscle activities associated with stance and swing phase during walking were identified. Results on FSR showed that stance and swing phases were detected by FSR signals during a gait cycle. Eight gait phases－initial contact, loading response, mid stance, terminal stance, pre swing, initial swing, mid swing, and terminal swing- were classified.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.778-783
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• 1999

The effect of carbon fiber orientation on the tribological properties of carbon fiber/epoxy composites used as a reflecting material for the electromagnetic wave has been investigated. It was found that the carbon fiber/epoxy composite which slides normal to prepreg lay-up direction had less friction and wear that those slides parallel to prepreg fiber lay-up direction due to the increase of delamination between carbon fiber and epoxy. Composite with unidirectional orientation($0/0^{\circ}$) had higher tribological properties than those with multidirectional orientation($0/45/90/-45^{\circ}$ and $0/90^{\circ}$) when the sliding direction was normal to prepreg lay-up direction. This was caused by the debonding between carbon fiber and epoxy which is proportional to contact area between the sliding surface and carbon fiber. Opposite results have been found when the sliding direction was parallel to prepreg lay-up direction due tot he tensile force applied on carbon fiber. In addition, it was shown that wear factor increased with increasing sliding velocity but the friction coefficient did not depend upon the sliding velocity.

• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.441-448
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• 2014

From several researches, recently, it was found that using hollowed precast concrete (HPC) column made more compact concrete casting in joint region possible than using normal solid PC (Precast concrete) column. Therefore, the rigidity of joints can be improved like those of monolithic reinforced concrete (RC). After filling the hollow with grout concrete, however, it is expected that the HPC column behaviors like composite structure since PC element and grout concrete have different materials as well as there is a contact surface between two elements. These may affect the structural behavior and strength of the composite column. A compressive strength test was performed for the HPC column with parameter of hollow ratio for the case with and without grout in the hollow and the result is presented in this paper. The hollow ratios in the test are 35, 50 and 59% of whole section of column. Concentrated axial force was applied to top of the specimens supported as pin connection for both ends. In addition, finite element (FE) analysis was performed to simulate the failure behavior of HPC column for axial compression. As a result, it was found that the hollow ratio did not affect the initial stiffness of HPC filled with grout regardless of the strength difference of HPC and grout. However the strength was increased inversely corresponding to the hollow ratio. The structural capacity of HPC without grout closely related to the hollow size. Especially, the local collapse governs the overall failure when the thickness of HPC is too thin. Based on these effect, a suitable equation was suggested for calculation of the compressive strength of HPC column with or without grout. FE analysis considering the contact surface between HPC and grout produced a good result matched to the test result.

• The korean journal of orthodontics
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• v.23 no.1 s.40
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• pp.1-15
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• 1993

This study was undertaken to investigate the midline having the least difference between the right and left structures among the lines that had been used in the study of the craniomaxillofacial asymmetry. The sample of this study consisted of twenty six Korean girls(average 18.9 years old) having normal facial appearance and occlusion. On the frontal cephalometric films of the sample, we divided the whole craniomaxillofacial area into four portions, i.e., cranial, upper facial, lower facial, and dental portion. So, we have found the midlines having the least difference in the whole craniomaxillofacial area itself, and in the each divided four portions, furtherly in the other portions from aimed portion. The findings were as follow: 1. In the whole craniomaxillofacial area, the connecting line between crista galli and anterior nasal spine and the perpendicular bisecting line between right and left foramen rotundums were suitable for the midline. 2. In the cranial portion, established all six lines were suitable for midlines. In the other portions, the perpendicular bisection line between both condylion, the line passing the contact point between right and left mandibular central insisiors among the perpendicular lines between right and left mandibular central incisial tips were suitable midlines fer evaluating the asymmetry of cranial portion. 3. In the upper facial portion, the perpendicular bisecting line between right and left zygions was the most suitable midline. In the other portions, the line between the crista galli and the most superior point of the odontoid process, the perpendicular bisecting line between right and left gonions, the perpendicular bisecting line between right and left condylions, and perpendicular bisecting line between right and left foramens rotundum were suitable midlines for evaluating the asymmetry of the upper facial portion 4. In the dental portion, the perpendicular bisecting lines between right and left buccal cusps of both maxillary first molars and between right and left mandibular first molars were suitable midlines. In the other portions, the perpendicular bisecting line between right and left landmarks crossing the lesser wing of the sphenoid bone and orbit, the perpendicular bisecting line between right and left mental foramens, and the connecting line between crista galli and prosthion were suitable midlines for evaluating the asymmetry of dental portion. 5. In the lower facial portion, the perpendicular bisecting lines between right and left condylions and between right and left gonions were suitable midlines. In the other portions, the line between the crista galli and anterior nasal spine, the perpendicular bisecting line between right and left foramen rotundums, and the perpendicular bisecting lines between right and left buccal cusps of both mandibular first molars and between right and left maxillary first molars were suitable midlines for evaluating the asymmetry of the lower facial portion.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.4
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• pp.420-430
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• 2022

Open bite is accompanied by decrease in tooth contact and overbite, and causes collapse of occlusal plane, mastication difficulties, speech disorders, changes in appearance, and lower occlusal force than normal. Open bite caused by temporomandibular joint disorder in adults with complete occlusion must be corrected after removal or stabilization of the causative factors. Orthodontic treatment, occlusal adjustment, prosthetic treatment, and surgical treatment can be the option of occlusal correction. This report describes about estimating the cause of occlusion change in two patients who developed an open bite due to mandibular displacement in adults with complete occlusion and different treatment approaches accordingly. In one patient, satisfactory result was obtained in functional and esthetic aspects through occlusal adjustment after stabilization of the temporomandibular joint.