• 한국구조물진단유지관리공학회 논문집
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• 제5권2호
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• pp.163-174
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• 2001

This paper is to study the characteristics of axial force behavior that operates to the part of turnout when it makes the turnout and the continuous welded rail unifying. The study is to model by using the 50kgN rail No. 15 turnout used in the domestic national railway and the UIC60 rail No. 18 turnout used in the rapid transit railway as the finite elements for analyzing the axial force behavior of the turnout by the continuous welded rail. It is to analyze the characteristics of behavior according to the change of creep resistance, ballast resistance and the change of parameter valuables of heel joint by the axial force simulation in making the continuous welded rail and then, it is to present the result. As the result of research on the parameter valuables through the analysis, it shows that the maximum axial force of turnout by the continuous welded rail are largely subordinated to the maximum resistance of heel joint and the fitting devices than the ballast resistance. Also it shows that the maximum axial force produced changes a lot according to the characteristics of creep resistance of the fitting part and the ballast resistance.

• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2415-2418
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• 2014

In this report, the contact resistance between "electrode" and "lead" is investigated for reasonable measurements of samples' resistance in a polypyrrole (PPy) nanowire device. The sample's resistance, including "electrode-lead" contact resistance, shows a decrease as force applied to the interface increases. Moreover, the sample's resistance becomes reasonably similar to, or lower than, values calculated by resistivity of PPy reported in previous studies. The decrease of electrode-lead contact resistance by increasing the applying force was analyzed by using Holm theory: the general equation of relation between contact resistance ($R_H$) of two-metal thin films and contact force ($R_H{\propto}1/\sqrt{F}$). The present investigation can guide a reliable way to minimize electrode-lead contact resistance for reasonable characterization of nanomaterials in a microelectrode device; 80% of the maximum applying force to the junction without deformation of the apparatus shows reasonable values without experimental error.

• 산업기술연구
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• 제20권B호
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• pp.95-103
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• 2000

A model trains must have similitude with its original model not only in shape but also in motion. Motion characteristics of a model train under considerations are maximum velocity in straight and circular tracks and stopping distance. Equations of motions are derived to obtain maximum speed and stopping distance based on the Newton's Second Law and the energy principal. To accurately predict traction and resistance force between wheel and rail. wheel slip, or creepage, is taken into consideration. To verify the equations of motion, various experiments have been carried out including measurement of gear efficiency, location of mass center, rolling resistance force, traction force, slip, maximum velocity and stopping distance. This paper addresses how the experiments are setup and carried out in detail. Also the results of experiments are compared with the analytical prediction, which showed good agreements with each other.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.128-134
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• 2013

High bending collapse performance (maximum resistance force and mean resistance force) of body center pillar is an important design target for vehicle safety against side impact. In this study, effect of the upper section shape and the thickness of outer reinforcement on bending collapse performance was investigated for the center pillar of a large passenger car. First, through bending collapse analyses using simple models with uniform section, an optimized center pillar upper section was chosen. Next, bending collapse performance for various models of the actual center pillar with changing the thickness of outer reinforcement were analyzed. The finally designed model showed distinctive enhancement in bending collapse performance nearly without weight increase.

• 전기학회논문지
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• 제59권7호
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• pp.1259-1264
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• 2010

This paper was researched about effectiveness of the electrochemical cell which is composed of the sea water and the Cu/Zn electrode. The electric potential difference between copper and zinc finally reached 0.51 volts. Short current decreased with time. It might depend on the electromotive force decreasing. Confirmed the load resistance and electrode affect in electromotive force and electric current. The resistance which shows a maximum output power was 20[$\Omega$], and the maximum output power from this resistance was evaluated as 0.736mW. In order to calculate the energy which creates from electrochemical cell, charging voltage of the capacitor with various capacitance was investigated. It was found that energy harvesting possibility of the cell which is made of a sea water electrolyte and the copper/the zinc.

• Structural Engineering and Mechanics
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• 제83권6호
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• pp.745-756
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• 2022

This study aims to determine the cause of the load resistance loss in storage racks that can be attributed to external forces such as earthquakes and to improve safety by developing reinforcement systems that can prevent load resistance loss. To this end, a static cyclic loading test was performed on pallet racks commonly used in logistics warehouses. The test results indicated that a pallet rack exposed to an external force loses more than 50% of its load resistance owing to the damage caused to column-beam joints. Three reinforcement systems were developed for preventing load resistance loss in storage racks exposed to an external force and for performing differentiated target functions: column reinforcement device, seismic damper, and viscoelastic damper. Shake table testing was performed to evaluate the earthquake response and verify the performance of these reinforcement systems. The results confirmed that, the maximum displacement, which causes the loss of load resistance and the permanent deformation of racks under external force, is reduced using the developed reinforcement devices. Thus, the appropriate selection of the developed reinforcement devices by users can help secure the safety of the storage racks.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1782-1793
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• 2008

Republic of korea has begun operating high speed train service according as KTX service operation starts in 2004. Also, EMU whose maximum speed is over 150 kph will be starting to service with electrification and improvement of existing railroad. Moreover, metropolitan electric railways have begun an express service to increase scheduled speed. Therefore, running resistance of rolling stock becomes more important factor effects on the performance. Running resistance of rolling stock is the factor which is necessary for the performance or operation plan of rolling stock, and it's related to rolling friction, slip friction, drag force, gradient, acceleration, curvature, tunnel condition and so on. It is possible to be calculated by CFD (Computational Fluid Dynamics). However it is predicted by experimental equation from running resistance test because of the complex calculation and manifold variables. In this paper, studies about running resistance of rolling stock is introduced, and each term of experimental equation is studied through theoretical approximation. Also, running resistance of rolling stock is estimated by the result of running resistance test, and effects being related to friction, drag force, gradient is examined.

• Restorative Dentistry and Endodontics
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• 제48권1호
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• pp.10.1-10.9
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• 2023

Objectives: This study compared the buckling resistance of 3 nickel-titanium (NiTi) retreatment file systems and the torque/force generated during retreatment. Materials and Methods: The buckling resistance was compared among the D-RaCe (DR2), HyFlex Remover, and Mtwo R25/05 retreatment systems. J-shaped canals within resin blocks were prepared with ProTaper NEXT X3 and obturated by the single-cone technique with AH Plus. After 4 weeks, 4 mm of gutta-percha in the coronal aspect was removed with Gates-Glidden drills. Retreatment was then performed using DR1 (size 30, 10% taper) followed by DR2 (size 25, 4% taper), HyFlex Remover (size 30, 7% taper), or Mtrwo R25/05 (size 25, 5% taper) (15 specimens in each group). Further apical preparation was performed with WaveOne Gold Primary. The clockwise torque and upward force generated during retreatment were recorded. After retreatment, resin blocks were examined using stereomicroscopy, and the percentage of residual filling material in the canal area was calculated. Data were analyzed using 1-way analysis of variance with the Tukey test. Results: The HyFlex Remover files exhibited the greatest buckling resistance (p < 0.05), followed by the Mtwo R25/05. The HyFlex Remover and Mtwo R25/05 files generated the highest maximum clockwise torque and upward force, respectively (p < 0.05). The DR1 and DR2 files generated the least upward force and torque (p < 0.05). The percentage of residual filling material after retreatment was not significantly different between file systems (p > 0.05). Conclusions: NiTi retreatment instruments with higher buckling resistance generated greater clockwise torque and upward force.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 춘계 학술논문 발표대회
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• pp.102-103
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• 2014

Due to the nature of the existing load, the criteria of assessing the intensity of the lightweight wall's impact resistance has been though of as obscure. The current study, therefore, focuses on the standardized assessment of the impact resistance to the force of the large soft body applying to the lightweight wall. The gypsum board wall showed a low level of the maximum residual displacement. It is, however, required to be careful about the selection of the finishing process since the high level of the maximum displacement is likely to cause harm to finishing materials. Unlike the gypsum board, the ALC block wall displayed a considerable rigidity while showing almost no maximum residual displacement. Even with the low level of the maximum displacement due to the stiffness, the ALC block wall is still likely to be affected by the vibration derived from any impact on the surface, which demands a need for additional study. The future experimental study, accordingly, will focus on the impact of the vibration on finishing materials, consequently leading to the accurate prediction of the possibility of potential damage to the lightweight wall caused by the large soft body.

• 대한물리치료과학회지
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• 제1권1호
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• pp.203-213
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• 1994

As a new concept of resistive exercise, isokinetic exercise was developed during the late 1960's. In isokinetic exercise, the subject works at a fixed speed aganist variable and totally accommodating resistance. During isokinetic exercise the resistance accommodates the external maintains maximum output throughout the full range of motion. The maximum torque during isokinetic movements is a measure of the muscular force applied in dynamic conditions.