• Physical Therapy Rehabilitation Science
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• 제12권1호
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• pp.56-61
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• 2023

Objective: Core training is a key exercise for conditioning and fitness programs, injury prevention, and more. This study aimed to find out the effect of adding dynamic core training, which is frequently prescribed in clinical practice, on dynamic balance and muscle activity compared to conventional static core training. Design: An experimental study Methods: This study is an experimental pilot study of prospective parallel design. Six healthy young adults were allocated to static core training group (SCG; crunch and plank) and blended group (BG; crunch, plank, and dead bug exercise) for two weeks to perform core training. Dynamic balance and muscle activity (erector spinae, rectus abdominis) were measured for all participants before and after core training. Results: All six healthy young adults enrolled completed the study. No significant difference was found before and after 6 sessions of core training in each group (P>0.05). Likewise, no significant difference was found in the results of the difference comparison between groups (P>0.05). Conclusions: In conclusion, in this experimental study, no difference was found when dynamic core training was added. Although the results before and after core training did not show improvement in dynamic balance and muscle activity, a randomized controlled trial is needed considering the results of previous studies and the limitations of this experimental study.

• Fibers and Polymers
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• 제5권1호
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• pp.25-30
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• 2004

The present paper reports the impact of thermal treatment on the characteristics of core-sheath type hybrid technical yarns. The core-sheath type hybrid yams are prepared using DREF-III technology. Polyester and glass multifilaments are used as core components whereas the cotton and polyester staple fibers are the sheath components wrapped around the core filament with different proportions to form a hybrid structure. The thermal treatment is carried out both in dry and in wet state under relaxed condition and the thermal shrinkage, sheath-slipping resistance and tensile and bending properties of hybrid yarns have been studied. Thermal treatment markedly increases the thermal shrinkage and sheath-slipping resistance of hybrid yarns with polyester multifilament in core, but insignificant effect for yarns with glass multifilament in core. Breaking elongation of hybrid yams with polyester multifilament in core increases with treatment temperature. The hybrid yarns with glass multifilament in core are least affected by thermal treatment.

• Design & Manufacturing
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• 제9권2호
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• pp.34-37
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• 2015

The HEV Traction Motor Core manufacturing technology is a core component of HEV Traction Motor Core (Iron Core) is a key technology for the manufacture of eco-friendly automotive industry is essential for the competitiveness of the country must obtain the technology. In this study, the HEV Motor Core of the Rotor manufacturing technology, the Stator manufacturing technology applied to Press Lamination Die and Core(Iron Core) was developed and the results are discussed.

• East Asian mathematical journal
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• 제35권2호
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• pp.163-172
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• 2019

In recent years, the term core literacy has been popular in educational circles all over the world, and there are more and more research on core literacy. At the same time, the mathematical culture has also been highly valued on a global scale. The mathematical culture is a part of college students' cultural quality, and then, what is the connection between the mathematical culture and mathematical core literacy? How to improve the mathematical core literacy of contemporary college students? This paper gives the corresponding answers to these two questions. By illustrating the concrete implementation of the course "Mathematical Culture" offered by Yanbian University, this paper discusses various measures for cultivating students' core qualities in Chinese universities. It must be useful and promote the research on mathematical core literacy for the educators in various countries.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.251-254
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• 2003

In this study, main works are focused on investigating the stress distribution at the interface between a rotor core and Cu bar when a punch is applied into the body of Cu bar. A parametric study with dimensional changes of core slot was performed numerically to identify what factors are dominant in producing high contact forces in the interface. As analysis results, it was found that core slot length was a dominant factor in increasing contact force at the interface between a rotor core and Cu bar.

• 전기학회논문지
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• 제58권2호
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• pp.356-362
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• 2009

The ELectromagnetic Core Imperfection Detector (EL-CID) test was performed on a small generator in the laboratory and a gas turbine generator in the field to assess the fault condition of generator stator core. Artificial defects with six different sizes were introduced in the small generator. The scan results on six defects show a very large increase in the magnitude of fault current compared to that obtained with a healthy core. After the stator core heats up, a thermal imaging camera was used to detect hot spot on the inner surface of the core for comparison. Several faults were found during inspection of the gas turbine generator with the EL-CID. It has been shown that the existence of a fault can be determined by monitoring the magnitude of fault current.

• 대한치과보철학회지
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• 제36권2호
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• pp.366-378
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• 1998

Post and core is used to restore endodontically treated teeth, and it is a very important part which supplies retention and support to the prosthesis. But occasionally, caries occured due to the microleakage at the post and core and tooth interface, the failure of prosthesis has happened. In this study, the microleakage of cast gold post and core, amalgam core, and composite resin core was investigated and compared. The coronal part of the extracted upper anterior teeth were removed and endodontically treated with conventional method. The teeth were divided into three groups. In group 1, cast gold post and core was cemented with resin cement and in group 2, ready-made post was cemented with resin cement and amalgam core was built. In group 3, ready-made post was cemented with resin cement and composite resin core was built. All specimens were thermocycled between $5^{\circ}C\;and\;55^{\circ}C$ with dwell time of 15 seconds, and immersed in 0.5% aqueous solution of basic fuchsin dye for 24 hours. After embedded in the epoxy resin, the specimens were sectioned longitudinally and observed with stereomicroscope with the magnification of 25. From the findings of this study, the following conclusions were obtained. 1. There was microleakage at the core/tooth interface of all specimens. 2. The microleakage of gold post and core was significantly less than those of the other two groups. 3. There was no significant difference between the microleakage of amalgam core and that of composite resin core.

• Transactions on Electrical and Electronic Materials
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• 제18권2호
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• pp.97-102
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• 2017

A current transformer (CT) is a type of sensor that consists of a combination of electric and magnetic circuits, and it measures large ac currents. When a large amount of current flows into the primary winding, the alternating magnetic flux in the iron core induces an electromotive force in the secondary winding. The characteristics of a CT are determined by the iron core design because the iron core is saturated above a certain magnetic flux density. In particular, when a large current, such as a current surge, is input into a CT, the iron core becomes saturated and the induced electromotive force in the secondary winding fluctuates severely. Under these conditions, the CT no longer functions as a sensor. In this study, the characteristics of the secondary winding were investigated using the time-difference finite element method when a current surge was provided as an input. The CT was modeled as a two-dimensional analysis object using constraints, and the saturation characteristics of the iron core were evaluated using the Newton-Rhapson method. The results of the calculation were compared with the experimental data. The results of this study will prove useful in the designs of the iron core and the windings of CTs.

• Design & Manufacturing
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• 제9권1호
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• pp.9-13
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• 2015

The HEV/EV Traction Motor Core manufacturing technology is a core component of Traction Motor Core is a key technology for the manufacture of eco-friendly automotive industry is essential for the competitiveness of the country must obtain the technology. This study was performed to develop a Rotor Core of the HEV/EV Traction Motor using the first time in Korea multi-gate BMC injection molding technique. Executed by the experiment of this study are as follows. Study 1: Developed a multi-gate BMC injection mold for the magnet fixed to the Rotor Core. Study 2: Developed a production implementation and manufacturing technology of the Rotor Core. In this study, the develop products and manufacturing technologies implemented by the BMC injection mold development for Magnet fixed to the Rotor Core and the results are discussed.

• Journal of Magnetics
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• 제22권1호
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• pp.93-99
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• 2017

The effort attempts to investigate the influence of various non-oriented electrical steel sheets on the core loss of a switched reluctance motor (SRM). The core loss of the motor inherits a strong correlation with flux density and permeability of the material. The study involves the use of laminated 2.7 % high silicon steel suitable for the motor in view of its higher flux density and lower core loss. The accurate prediction of core loss leaves way to suggest measures for improving the performance of the SRM. The dynamic simulation measurements of a 1.5 kW, three-phase 12/8 SRM involve the finite element method (FEM) and use the data obtained experimentally from Epstein frame. The closeness of the simulated and hardware results obtained with laminations of M400-50A, DI MAX-M19 and DI MAX-M15 both for the stator and rotor, espouse a greater significance to the findings in terms of the core loss density and forge new dimensions for its use in the drive industry.