• Korean Journal of Applied Biomechanics
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• v.13 no.2
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• pp.123-137
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• 2003

This study is to present more effective starting skills through analysis of kinematic characteristics of starting motions in 300m Time Trials of Inline Skating. To achieve this goal, 6 athletes, 3 in the national team and 3 in business teams were chosen and their starting motions were examined with three-dimensional image analyses. The results of analyses in regard of positions and speed of the bodily center and angles, angular velocity, and linear velocity of articulations of lower limbs by sections of starting motions are as follows: In case of the central position, though it is effective to reduce the air resistance by lowering the upper part of the body maximumly, it is reasonable to accelerate by raising the upper part of the body to some degree for the running posture at the lower speed in the starting section. In the starting section, it is efficient to minimize the period of time in touching the ground. for this, it is necessary to train for taking motions without slippage while touching the ground. While 3 athletes in business teams kicked the ground as running right after the starting, the others in the national team slid on the ground. As the number of steps increased, the movable speed changed quickly. Thus the movable speed of athletes in the national team indicated big differences in two to three steps. If these factors are well supported, the push-away starting method might be better than the running starting method in terms of improvement of records.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.267-275
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• 2012

Austenite stainless steel 304 has properties of high resistance to corrosion and temperature changes. Therefore, this material is widely used in various of industries. However, when the material is subjected to heating and cooling cycles the forming accuracy, for example, the right angle associated with a sharp bend such as corner is lost. This phenomenon is caused by the reversion of the deformation-induced martensite into austenite when the temperature in increased. This result in misfit of a structure or an assembly, and an increase in residual stress. Hence, it is important to understand this process. In this study, to evaluate the mechanical behavior of the deformation-induced martensite and reversed austenite, a scanning acoustic spectroscope including the capability of obtaining both phase and amplitude of the ultrasonic wave (i.e., the complex V(z) curve method) was used. Then, the velocities of the SAW propagating within the specimens made in different conditions were measured. The experimental differences of the SAW velocities obtained in this experiment were ranging from 2,750 m/s to 2,850 m/s, and the theoretical difference was 3.6% under the assumption that the SAW velocity was 2,800 m/s. The error became smaller as the martensite content was increased. Therefore, the SAW velocity may be a probe to estimate the marternsite content.

• Korean Journal of Applied Biomechanics
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• v.29 no.2
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• pp.105-112
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• 2019

Objective: The main purpose of this study was to investigate the effects of wearing an ankle weight belt while performing gait in water by focusing on the effect of using ankle weights have on the gait kinematics and the muscle activities for developing optimum training strategies. Method: A total of 10 healthy male university students were recruited for the study. Each participant was instructed to perform 3 gait conditions; normal walking over ground, walking in water chest height, and walking in water chest height while using ankle weights. All walking conditions were set at control speed of $4km/h{\pm}0.05km/h$. The depth of the swimming pool was at 1.3 m, approximately chest height. The motion capture data was recorded using 6 digital cameras and the EMG was recorded using waterproof Mini Wave. From the motion capture data, the following variables were calculated for analysis; double and single support phase (s), swing phase (s), step length (%height), step rate (m/s), ankle, knee, and hip joint angles ($^{\circ}$). From the electromyography the %RVC of the lower limb muscles medial gastrocnemius, rectus femoris, erector spinae, semitendinosus, tibialis anterior, vastus lateralis oblique was calculated. Results: The results show significant differences between the gait time, and step length between the right and left leg. Additionally, the joint angular velocities and gait velocity were significantly affected by the water resistance. As expected, the use of the ankle weights increased all of the lower leg maximum muscle activities except for the lower back muscle. Conclusion: In conclusion, the ankle weights can be shown to stimulate more muscle activity during walking in chest height water and therefore, may be useful for rehabilitation purposes.

• The korean journal of orthodontics
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• v.17 no.2
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• pp.185-200
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• 1987

This paper was undertaken to observe the displacement of craniofacial complex with cervical headgear and to compare narrowing or widening effect of palate by use of contraction or expansion face-bow, respectively. The 3-dimensional finite element method(FEM) was used for a mathematical model composed of 597 nodes and 790 elements and an electrical resistance strain gauge investigation was performed to validate the finite element model. The outer bow of cervical headgear was adjusted to be placed below the occlusal plane by $25^{\circ}$ and met the midsagittal plane by $40^{\circ}$, and was loaded 1kg on each right and left hook toward posterior direction. The results were as follows 1. Generally, the maxillary teeth and facial bone were displaced in posterior, medial and downward direction. 2. It was the maxillary 2nd bicuspid that moved bodily. 3. The craniofacial complex rotated in a clockwise direction around the rotating axis which lay from the most posterior and lowest point connecting nasal crest of maxillary bone and vomer, progressively toward a more posterior, lateral and upward direction, anterior and upper area of pterygomaxillary fissure, base of medial pterygoid plate and laterally to the contact area of zygomatic arch with squamous part of temporal bone. 4. No contraction effect was observed by contraction face-bow when compared to the standard face-bow. 5. In case of expansion face-bow, the areas of maxillary 2nd bicuspid, molars and palate were expanded remarkably.

• Clinical and Experimental Vaccine Research
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• v.12 no.4
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• pp.328-336
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• 2023

Purpose: Human peripheral blood mononuclear cell (PBMC)-based in vitro systems can be of great value in the development and assessment of vaccines but require the right medium for optimal performance of the different cell types present. Here, we compare three commonly used media for their capacity to support innate and adaptive immune responses evoked in PBMCs by Toll-like receptor (TLR) ligands and whole inactivated virus (WIV) influenza vaccine. Materials and Methods: Human PBMCs were cultured for different periods of time in Roswell Park Memorial Institute (RPMI), Dulbecco's minimal essential medium (DMEM), or Iscove's modified DMEM (IMDM) supplemented with 10% fetal calf serum. The viability of the cells was monitored and their responses to TLR ligands and WIV were assessed. Results: With increasing days of incubation, the viability of PBMCs cultured in RPMI or IMDM was slightly higher than that of cells cultured in DMEM. Upon exposure of the PBMCs to TLR ligands and WIV, RPMI was superior to the other two media in terms of supporting the expression of genes related to innate immunity, such as the TLR adaptor protein gene MyD88 (myeloid differentiation factor 88), the interferon (IFN)-stimulated genes MxA (myxovirus resistance protein 1) and ISG56 (interferon-stimulated gene 56), and the leukocyte recruitment chemokine gene MCP1 (monocyte chemoattractant protein-1). RPMI also performed best with regard to the activation of antigen-presenting cells. As for adaptive immunity, when stimulated with WIV, PBMCs cultured in RPMI or IMDM contained higher numbers of IFNγ-producing T cells and secreted more immunoglobulin G than PBMCs cultured in DMEM. Conclusion: Taken together, among the different media assessed, RPMI was identified as the optimal medium for a human PBMC-based in vitro vaccine evaluation system.

• Elastomers and Composites
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• v.21 no.4
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• pp.309-322
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• 1986

This survey reports on the extensive examination of the qualify of 14 jogging and tennis shoes separately, availavable in the domestic market, Both jogging and tennis shoes were catagorised in two groups, namely the general goods(less expensive ones) and the exclusive goods(expensive models). The detailed classification are shown below; The domestic products meet the general purpose just as that of the foreign products. Due to the adhesion technology, the domestic tennis shoes consist of rubber sole with natural leather upper;In fact, the desirable combination, as foreign products, must be polyurethane/natural leather. The expensive models were heavier than the less expensive ones. The greater weight difference of right and left shoes are shown in the expensive models than that of the less expensive ones. The moisture absorption ratio of the expensive model is far superior in comparison with the less expensive model. The reason is identified by the material supplyed to produce the expensive model consisted of the natural leather and proper parts. The abrasion resistance of the expensive models were excellent that of the less expensive ones, because the rubber soles were showed the properties better than polyurethane sole which was used in the less expensive model.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.152-158
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• 2015

The Korean Government said that it issued advance notice of the amendment of medical act article 34 on Oct. 29 of last year. Another issue at the heart of controversy in 2009 was telemedicine between doctors and patients for the purpose of helping those in the dead zone of medicine and supporting medical service industry. It failed, however, to enact legislation due to the strong opposition from medical profession as well as the apprehension about abuse of medical treatment and the rise of medical expenses. To amend and legislate a law, it is needed in advance to examine and analyze the rationality, propriety and feasibility of it. In particular, when it comes to amending a medical act, the validity should be acknowledged only when the right to life and health of the people is protected. Medical act article 34 is in the state of drift because of stiff resistance from medical and civic groups. This study purpose of analyze and to explain the amendment of recent proposition of Medical Act Article 34 and to suggest possible improvement methods.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.1
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• pp.1-5
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• 1984

The author carried out an experiment for the dynamical swimming force of crusian carp, Carassius carassius. The experimental water tank was made of 4mm thick transparent acryl board in the right hexahedral shape (400L$\times$240W$\times$800H mm). The water temperature in the tank ranged 20.6$^{\circ}C$ to 21.2$^{\circ}C$. The water level in the tank was maintained 70cm high from the bottom. The measurement of the swimming force was carried out by use of strain gauge. The results obtained can be summarized as follows: 1) The momentary maximum swimming force F sub(M) (g) and the sustainable maximum swimming force F sub(s) (g) can be expressed as a function of the body weight W(g). F sub(M) =1.45W, F sub(s) =0.29W where the momentary maximum swimming force means the highest value, and the sustainable maximum swimming force means the mean high value sustained for 4 to 5 seconds presented in the recording paper. 2) F sub(M) and F sub(s) can be expressed as a function of the body length L(cm). F sub(M) =0.11L super(2.63), F sub(s) =0.15L super(1.77) 3) The coefficient of hydraulic resistance for crusian carp was derived as 0.287.

• Journal of radiological science and technology
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• v.45 no.3
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• pp.233-239
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• 2022

In the radiology department, where radiation is used in medical institutions to perform examinations with various equipment, the field of surgical treatment is the intervention angiography room. Accordingly, strict infection control is required. The purpose of this study was to determine the contamination status by detecting pathogens before and after disinfection in the intervention angiography room, and to determine the degree of death by using a disinfectant, sodium dichloride isocyanurate, which is mainly used in the intervention angiography room. The subjects were 10 medical institutions of general hospital level or higher with an intervention angiography room in the P city, and 12 places with high contact frequency during examinations and procedures were sampled and requested to an analysis institution. As for the sample collection method, up/down, left/right directions were used to increase precision. Before disinfection, all procedures were completed, and after disinfection, exposure was performed using a disinfectant for at least 10 minutes, and detection was performed using a transport medium. As a result, in the pathogen analysis, most pathogens were detected in a humid environment or in a place with high contact frequency for microorganisms to thrive. The detected pathogens were found in the general environment or were human flora. It is a pathogen that does not cause disease under normal healthy host conditions. However, it was found to be an opportunistic infection that causes opportunistic infection depending on the case or situation in which the body's resistance is weakened. In addition, as a result of using the disinfectant mainly used in the intervention angiography room, it was found that more than 93.3% of them died. Therefore, the data of this study will be used as good basic data for the evaluation of pathogens in the intervention angiography room and will be of great help in infection control.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.3
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• pp.284-292
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• 2020

In this study, hydrogen charging was conducted for API X70 steel by the electro-chemical hydrogen charging method. Right after hydrogen was diffused from the specimen surface to the inside of the X70, the small punch tests and hydrogen concentration analysis was conducted within 5 minutes. Hydrogen was analyzed by melting the whole specimen and detect the gas after melting. Mechanical properties were measured by the small punch (SP) testing. Fracture surface and specimen surface were observed using scanning electron microscope. Three tests were repeated for study sensitivity of the SP test results under a same charging condition. It was observed that the variation of the maximum load, SP displacement at failure, hydrogen concentration as the charging period was not much in the case of X70 as the other steel such as Inconel. It can be argued that X70 base metal may have high hydrogen damage resistance and hydrogen diffusion in the base metal would not cause much embrittlement. Limitations of the SP test with 0.5 mm thickness for hydrogen damage test for X70 were discussed.