• 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.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.335-341
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• 1997

The generic analysis method for core flow instability is suggested to confirm that the core flow instability would not occur on PWR conditions. For the confirmation, the stability criteria of each fuel type are provided. Instability investigations in various accident conditions prove that the locked rotor accident is the most limiting case to instability. Parametric Effects are surveyed and in good agreement with available studies. The effects of heat flux distribution become negligible as the subcooling number is decreased. The power margin to instability is calculated quantitatively in various accident conditions.

• Structural Engineering and Mechanics
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• 제52권2호
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• pp.323-349
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• 2014

In this paper, linear buckling analysis of a curved sandwich beam with a flexible core is investigated. Derivation of equations for face sheets is accomplished via the classical theory of curved beam, whereas for the flexible core, the elasticity equations in polar coordinates are implemented. Employing the von-Karman type geometrical non-linearity in strain-displacement relations, nonlinear governing equations are resulted. Linear pre-buckling analysis is performed neglecting the rotation effects in pre-buckling state. Stability equations are concluded based on the adjacent equilibrium criterion. Considering the movable simply supported type of boundary conditions, suitable trigonometric solutions are adopted which satisfy the assumed edge conditions. The critical uniform load of the beam is obtained as a closed-form expression. Numerical results cover the effects of various parameters on the critical buckling load of the curved beam. It is shown that, face thickness, core thickness, core module, fiber angle of faces, stacking sequence of faces and openin angle of the beam all affect greatly on the buckling pressure of the beam and its buckled shape.

• 한국염색가공학회지
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• 제5권1호
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• pp.19-25
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• 1993

Plastic optical fibers(POFs) composed of poly(methylmethacrylate) (PMMA), polystyrene (PS), or polycarbonate(PC) as a core materials, and of fluorinated polymer or PMMA as a cladding were fabricated and their properties were investigated in this study. The attenuation loss of PMAA core POF was about 1,700 dB/Km at 660 nm, the loss of PS core POF was 1,800 dB/Km at 560 nm, and the loss of PC core POF was 2,200 dB/Km at 780 nm. These attenuation losses of POFs prepared ill this study were higher than those of commerically available POFs. Compared to PMMA and PS core POFs, PC core POF has excellent characteristics, including high thermal stability, high flexibility, and high impact strength.

• Journal of Electrical Engineering and Technology
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• 제6권4호
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• pp.527-534
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• 2011

In the present paper, the characteristics of Mega-Flux$^{(R)}$, JNEX-Core$^{(R)}$, amorphous and ferrite cores are compared to the inductor of buck-boost converters for Hybrid Electric Vehicles. Core losses are analyzed at the condition of 10 kHz sine wave excitations, and permeability fluctuations vs. temperature and magnetizing force will be analyzed and discussed. Under the specifications of the buck-boost converter for 20 kW THS-II, the power inductor will be designed with Mega-Flux$^{(R)}$ and JNEX-Core$^{(R)}$, and informative simulation results will be provided with respect to dc bias characteristics, core and copper losses.

• Computers and Concrete
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• 제27권4호
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• pp.369-383
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• 2021

This article deals with the frequency analysis of viscoelastic sandwich disk with graphene nano-platelets (GPLs) reinforced viscoelastic concrete (GPLRVC) face sheets and honeycomb core. The honeycomb core is made of aluminum due to its low weight and high stiffness. The rule of the mixture and modified Halpin-Tsai model are engaged to provide the effective material constant of the concrete. By employing Hamilton's principle, the governing equations of the structure are derived and solved with the aid of the Generalize Differential Quadrature Method (GDQM). In this paper, viscoelastic properties are modeled according to Kelvin-Voigt viscoelasticity. The deflection as the function of time can be solved by the fourth-order Runge-Kutta numerical method. Afterward, a parametric study is carried out to investigate the effects of the outer to inner radius ratio, hexagonal core angle, thickness to length ratio of the concrete, the weight fraction of GPLs into concrete, and the thickness of honeycomb core to inner radius ratio on the frequency of the viscoelastic sandwich disk with honeycomb core and FG-GPLRVC face sheet.

• 한국융합학회논문지
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• 제11권3호
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• pp.245-252
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• 2020

본 연구는 요가, 필라테스, 코어운동 등 체간 안정성 운동프로그램 적용 전후의 만성 요통 환자의 기능적 움직임, 동적 균형능력 및 체간 안정성의 변화를 확인하고, 3가지 체간 안정성 운동의 효과를 비교하고자 하였다. 만성 요통을 가진 성인 43명을 요가 집단 (n=15)과 필라테스 집단 (n=15) 및 코어 운동 집단 (n=13)으로 분류하였고, Functional Movement Screen (FMS)와 Lower Quater Y-Balance Test (YBT-LQ) 및 Trunk Stability Test (TST)를 통해 기능적 움직임, 동적 균형능력 및 체간 안정성을 각각 측정하였다. 이후 8주간 운동을 적용한 후 모든 변인을 재측정하였으며, 운동 적용 전후 차이를 비교 분석하였다. 그 결과, 세 집단 모두 운동 적용 후 FMS, YBT-LQ 및 TST의 측정값이 적용 전보다 유의하게 증가하였으나, 각 운동 적용에 따른 집단 간의 차이는 나타나지 않았다. 이런 결과는 요가, 필라테스 및 코어 운동이 만성 요통 환자의 기능적 움직임, 동적 균형능력 및 체간 안정성을 개선하는 데 도움이 된다는 것을 보여주었다.

• 미생물학회지
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• 제29권2호
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• pp.80-84
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• 1991

We cloned and expressed hepatitis B viral core antigen (HBcAg) gene in E. coli using $P_{L}$ promoter system. For optimal expression of the gene, we undertook the studies on the effects of the distance between Shine-Dalgarno (SD) sequence and start codon, copy number of repressor gene, induction temperature, and the stability of the core antigen. The results demonstrated that the induction at 37.deg.C was more efficient than at 42.deg.C, and the 11 base pairs (bp) distance between SD sequence and start codon of HBcAg gene was more efficient than the 15 bp distance in E. coli. The copy number of cI857 repressor gene did not influence on the expression of HBcAg, and the expression level of HBcAg in mutant type (low protease activity) and wild type strains was almost the same. The produced core antigen appeared to be HBcAg not HBeAg judged by two different radioimmunoassat (RIA) kits. This result suggested that the antigen was stable in E. coli.i.

• 한국분무공학회지
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• 제11권3호
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• pp.147-154
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• 2006

A specially designed injector using electric conductivity was used to measure the liquid film thickness accurately. The measurement conducted through the precise calibration, accuracy is demonstrated in comparison with the previous theory and the results using other measurement method. The tendency of liquid film thickness for geometric parameters was examined by the precise measurement. The variation of air core and stability are examined through the visualization of the formation of air core in swirl chamber and the variation of liquid film thickness by the time.

• 토지주택연구
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• 제14권1호
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• pp.115-122
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• 2023

최근 Covid-19 및 건설현장 인력 고령화 등으로 인하여 공동주택 생산성은 악화되고 있는 실정이다. 이에 탈현장(Off-Site Construction) 기반의 공장생산 방식으로의 공동주택 건설 방향 전환이 필요하다. 모듈러 공법은 공기단축이 가능하여 스마트 건축시스템으로 각광받고 있다. 이 연구에서는 모듈러 공법의 공기단축을 극대화 할 수 있는 PC코어 시스템을 개발하고, 구조성능을 해석적 연구를 통하여 검증하였다. 제안된 PC코어 시스템은 완전 PC형태로 이루어져 있으며, 접합방식은 건식 접합이다. 연구 결과, 제안된 PC코어 시스템은 모듈러 주택에 사용가능한 구조성능을 확보한 것으로 나타났다.