• 한국공작기계학회논문집
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• 제14권2호
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• pp.104-109
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• 2005

This article has been investigated the use of FFT for adhesive joints analysis between metal sheets. The method is based on the measurement of the reflection wave at the metal/adhesive interface. After describing briefly the physical aspects of the phenomenon, an index is defined to detect defective zone of the joint(both for the lack of adhesive and for insufficient adhesion): the influence of the experimental variables(variable stress...) on the measurement is discussed. By means of a control experiment it is shown that stress variation in adhesive joints are separate to be distinguished. In this paper, Nondestructive evaluation in adhesive joints are evaluated together with ultrasonic testing and finite element analysis.

• 한국환경생태학회지
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• 제37권6호
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• pp.464-472
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• 2023

중년여성은 발달주기 상 신체적, 정신적 스트레스를 많이 받는 시기이다. 이러한 스트레스는 만성적인 고통과 질병으로 연결되기 때문에 삶의 질을 저하시키는 원인이 된다. 이에 대한 대안으로 산림치유가 주목받고 있다. 산림치유는 산림의 치유적 요소를 통해 인간의 건강을 향상시키는 것을 말한다. 이에 본 연구는 감각통찰기반 산림치유 프로그램이 중년 여성의 스트레스 저감에 효과가 있는지를 확인하기 위하여 수행되었다. 이를 위해 산림치유 프로그램에 참가하기를 원하는 중년 여성을 모집하여 실험집단과 통제집단으로 각 20명씩 무작위 배정하여 사전-사후 검사를 실시하였다. 산림치유 프로그램은 감각과 통찰 기반으로 6시간 8회기로 구성되었다. 산림치유 프로그램 장소는 제주 사려니숲에서 진행하였으며, 측정도구는 지각된 스트레스, 여가만족도, 맥파검사를 통한 스트레스 지수를 측정하여 비교하였다. 연구 결과 산림치유 프로그램은 스트레스를 낮추고, 여가만족도를 향상시키는 것으로 나타났다.

• 대한한의진단학회지
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• 제15권3호
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• pp.245-260
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• 2011

Objectives: The aim of this experiment is to know the effect of Mountain Cultivated Ginseng Pharmacopuncture on Heart Rate Variability (HRV), Pulse wave velocity (PWV) in Middle Aged Women. Methods: We investigated on 40 women of breast cancer patients. First, we measured their Heart Rate Variability(HRV), Pulse wave velocity (PWV) and then Mountain Cultivated Ginseng Pharmacopuncture $20m{\ell}$ were injected on them. After 30 minutes, we measured Heart Rate Variability(HRV), Pulse wave velocity(PWV) again. As a result, method of non-equivalent control group non-synchronized design were used for evaluation. Results: In HRV, Mean HRV is significantly decreased from 69.15 to 63.34 after injection. Mean RR is significantly increased from 877.20 to 962.10 after injection. SDNN is significantly increased from 32.56 to 41.34 after injection. PNN50 is significantly decreased after injection. RNSSD, SDSD, TP, VLF is significantly increased after injection. Stress Resistance ability is significantly increased from 37.55 to 44.60 after injection. And In PWV, E-R, E-L, H-R, H-L is significantly decreased after injection. Conclusions: Effect of Mountain Cultivated Ginseng Pharmacopuncture on Heart Rate Variability (HRV) increased adaptability of autonomic nervous system and on Pulse wave velocity (PWV) decreased arterial stiffness.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2007년 가을학술발표회
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• pp.334-344
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• 2007

This paper performed a comprehensive evaluation of the results of the 2007 Ground Response Analysis Round Robin Test, at which 14 institutions and individuals participated. The submitted results showed significant discrepancies. The main reason for this difference has been attributed to the dispersion in the estimated shear wave velocity profiles and dynamic soil curves. It is therefore concluded that accurate evaluation of the material properties is of primary importance for reliable estimation of the ground vibration. Evaluation of the effect of the analysis method showed that the equivalent linear analysis overestimates the peak ground acceleration, but overall the results are similar to a total stress nonlinear analysis. However, the total and effective stress nonlinear analyses show distinct discrepancies, the effective stress analyses consistently resulting in a lower response due to the development of the excess pore water pressure and thus softer response.

• 생명과학회지
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• 제26권3호
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• pp.346-352
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• 2016

전통적으로 향기(aroma) 치료법은 대체 의학 분야에서뿐만 아니라 정신과 치료에서도 실제로 널리 활용 되었다. 본 연구에서는 일차적으로 odorant-binding protein (OBP) 활성 부위에 대한 스마트 웨이브(SW) 주요 화학적 조성물과 OBP 활성 리간드인 citrate anion 결합 친화도를 비교 분석하였다. SW는 OBP 활성 부위에 대해 citrate anion보다 훨씬 높은 분자 결합 친화도를 나타내었다. 임상적으로 SW혼합 조성물을 후각으로 흡입한 전/후, 뇌파에 어떠한 변화가 유도되는지를 비교 분석하였다. 18명의 피험자들을 대상으로 SW 흡입 전/후 뇌파의 명상(안정감) 변화 지수를, 악취를 내는 음성 대조군(EV)과 파우더향을 발산하는 양성 대조군(HB) 흡입 전/후의 변화 값과 비교하였다. SW를 흡입한 실험군에서는 SW를 흡입하고 난 후 상쾌함을 경험하였다는 반응을 나타냈으며 SW흡입군에서는 EV흡입군과 HB흡입군에 비하여 뇌파의 명상 지수가 현저하게 안정된 값으로 유도되는 것을 확인하였다. 또한 EV흡입 이후 SW를 흡입하였을 때 뇌파 명상 지수가 안정 뇌파값 범위로 개선되었다. 결과적으로 SW혼합 조성물은 OBP에 효과적으로 결합하여 OBP를 활성화 시키고, SW 흡입은 뇌파를 효과적으로 통제하여 심리적 상태를 현저하게 안정화 시키는 것을 확인하였다. 본 연구를 통하여 SW흡입법은 외부의 스트레스 자극으로부터 뇌 활성을 효율적으로 조절할 수 있는 새로운 향기 치료법으로의 활용이 가능하다고 판단된다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2009년도 학술대회 초록집
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• pp.198-202
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• 2009

스플릿 홉킨슨 압력 봉(SHPB)실험은 암석 및 콘크리트와 같은 취성재료의 동적 물성과 변형특성을 파악하고 압축 응력-변형율 데이터를 획득하기 위하여 사용된다. SHPB 실험법은 원리상 대상시료가 파괴이전에 동적응력평형 상태와 일정 변형율 속도 조건하여 놓여져 있어야 한다. 이러한 조건을 만족시키기 위하여 충격봉과 입사봉의 충격에 의하여 발생되는 충격 입사파형을 제어할 필요가 있다. 최근에는 원형 디스크를 충격봉과 입사봉 사이에 두어 입사 충격파형을 제어하는 펄스쉐이핑 기법이 적용되고 있다. 본 연구에서는 입사 충격파형을 정밀하게 제어할 목적으로 다양한 형태와 크기의 금속디스크를 대상으로 SHPB 실험을 수행하여 동적 변형 특성을 파악하였다. 펄스쉐이퍼의 두께와 직경이 작아짐에 따라 응력값과 파장은 증가하였다.

• 동서간호학연구지
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• 제18권2호
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• pp.111-119
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• 2012

Purpose: Recently, Neurofeedback training system that based on biofeedback of brain wave was introduced. This study was performed to identify the effects of the improvement of brain function by Neurofeedback training on elders(the 2nd or 3rd grade of long-term care insurance services). Methods: A quasi-experimental design using a nonequivalent control group, pre-post test was used. Total 11 elderly were enrolled in this study (experimental group 5, control group 6). The intervention was conducted 3 times a week for 30 minutes from January to June, 2012 (total 60 times). Chi-square test and Mann-Whitney U-test were used to analyze the data. Results: After the Neurofeedback intervention, attention quotient (AQ), anti-stress quotient (ASQ), emotion quotient (EQ) and brain quotient (BQ) of the experimental group were significantly better than those of the control group. Conclusion: The findings indicate that the Neurofeedback training program was effective in reducing fatigue by AQ, increasing the physical and mental stress resistance by ASQ, emotional balance by EQ and improving of total brain function by BQ. Therefore Neurofeedback training be used as an effective training intervention for the health of elderly in geriatric facility.

• Earthquakes and Structures
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• 제26권4호
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• pp.261-267
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• 2024

With the increase in the exploitation depth of offshore oil and gas, it is possible to control the global buckling of deep-sea pipelines by the snake lay method. Previous studies mainly focused on the analysis of critical buckling force and critical temperature of pipelines under the snake-like laying method, and pipelines often suffer structural failure due to seismic disasters during operation. Therefore, seismic action is a necessary factor in the design and analysis of submarine pipelines. In this paper, the seismic action of steel pipes in the operation stage after global buckling has occurred under the active control method is analyzed. Firstly, we have established a simplified finite element model for the entire process cycle and found that this modeling method is accurate and efficient, solving the problem of difficult convergence of seismic wave and soil coupling in previous solid analysis, and improving the efficiency of calculations. Secondly, through parameter analysis, it was found that under seismic action, the pipe diameter mainly affects the stress amplitude of the pipeline. When the pipe wall thickness increases from 0.05 m to 0.09 m, the critical buckling force increases by 150%, and the maximum axial stress decreases by 56%. In the pipe soil interaction, the greater the soil viscosity, the greater the pipe soil interaction force, the greater the soil constraint on the pipeline, and the safer the pipeline. Finally, the pipeline failure determination formula was obtained through dimensionless analysis and verified, and it was found that the formula was accurate.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.703-704
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• 2009

Natural gas Hydrate is an ice-like crystal containing natural gas it. Natural gas hydrate is studied as a new energy resource and a factor for seafloor slope stability and global warming. The unique pressure and temperature stability conditions of natural gas hydrate have challenged the research efforts. In this study, a new tool to study hydrate-bearing sediments and the preliminary results are introduced. The device can sustain 20MPa of the fluid pressure and apply 5MPa of the vertical effective stress under the temperature control. Cell can be scanned by X-ray CT scanner and also has the capability of multi-sensor data acquisition. Preliminary results suggests various application of the cell to hydrate-bearing research.

• Structural Engineering and Mechanics
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• 제3권4호
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• pp.391-410
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• 1995

The application of adaptive finite element method to dynamic problems is investigated. Both the kinetic and strain energy errors induced by space and time discretization were estimated in a consistent manner and controlled by the simultaneous use of the adaptive mesh generation and the automatic time stepping. Also an optimal ratio of spatial discretization error to temporal discretization error was discussed. In this study it was found that the best performance can be obtained when the specified spatial and temporal discretization errors have the same value. Numerical examples are carried out to verify the performance of the procedure.