스트레스는 자율신경계 반응의 변화를 수반하며, 특히 심박변이도 지표는 스트레스에 의한 자율신경계의 활동을 반영하는 양적 지표로 사용된다. 본 연구에서는 스트레스 완화를 위한 산소와 색채 조명의 복합 자극이 제시되는 동안 자율신경계 반응의 변화를 확인하였다. 42명의 실험참가자는 지난 2주 동안 경험한 스트레스에 대한 증상들을 스트레스 반응 척도에 평가하였다. 스트레스 평가 후, 실험참가자는 복합 자극을 제시받았고, 자극 제시 전과 후, 그리고 자극이 제시되는 동안 심전도 신호가 기록되었다. 자극 조건은 30% 농도의 산소와 백색 조명, 산소와 주황색 조명과 산소와 파란색 조명의 조합의 세 가지로 구성되었다. 심박률(HR), R-R간격의 표준편차(SDNN), 연속한 R-R 간격 차이 값의 평균제곱근(RMSSD)과 심박변이도의 저주파 성분(LF), 고주파 성분(HF), 그리고 LF와 HF의 비율을 심박변이도 지표로 추출하였다. 이들 지표는 자극 제시 전과 후의 평균을 비교하는데 활용되었다. 결과는 자극 조건이 제시되고 난 후, HR과 LF/HF ratio의 유의한 감소를 보여주었다. 특히, 산소와 파란색 조명이 제시된 조건에서 다른 두 조건보다 유의하게 큰 RMSSD와 HF의 증가 및 LF/HF ratio의 감소가 나타났다. 이는 30% 농도의 산소와 파란색 조명의 조건이 부교감신경 의 활성화에 의한 자율신경의 균형을 유발하여 스트레스 이완에 가장 효과적임을 보여주었다.
Until recently, almost all ETFE film structures that have been erected is the cushion type because there are problems at lower allowable strength under elastic range and viscosity behaviour such as creep and relaxation of ETFE films under long-term stresses. But the number of tension type structures is currently increasing. This paper proposes the stretch fabrication of ETFE film to verify the applicability of ETFE films to tensile membrane structures. First of all, to investigate the possibility of application on tensile membrane structures, the stretch fabrication test is carried out, and it is verified that it is possible to increase the yield strength of the film membrane structures. After simulating the experiment also carries out an analytical investigation, and the effectiveness of the elasto-plastic analysis considering the viscous behavior of the film is investigated. Finally, post-aging tension measurement is conducted at the experimental facilities, and the viscosity behavior resulting from relaxation is investigated with respect to tensile membrane structures.
Plastic deformation was observed by TEM around the intragranular SiC particles in the matrix for nanocomposite system. The dislocations are generated at selected planes and there is a tendency for the dislocations to form a subgrain boundary structure with low-angel grain boundaries and networks. In this study, dislocation generated in the matrix during cooling down from sintering temperatures by the highly localized thermal stresses within and/or around SiC particles caused from the thermal expansion mismatch between matrix and SiC particle was observed. In monolithic and microcomposite system. These phenomena is closely related to the plastic relaxation of the elastic stress and strain energy associated with both thermal misfitting inclusions and creep behaviors. The plastic relaxation behavior was explained by combination of yield stress and internal stress.
Zr-4 used for a cladding and an end plug of reactor component has creep deformation under operation at high temperature. Creep is regarded as the time dependent deformation of a material under constant applied stress. Although the major source of the deformation of zirconium component in water-cooled reactors is irradiation creep, the thermal creep may give a rise to significant deformation in reactor component especially at relatively high temperatures and at various constant stresses, and therefore it must be predicted accurately. Stress relaxation is the time dependent change of stress at constant strain and it is a process related intimately to creep. In this paper, the creep behavior and stress relaxation of Zr-4 is examined at the temperature of 500℃ that is 40% of the absolute melting temperature of Zr-4 under the stress below yield stress and under the various constant strains. The results obtained are summarized as follows: 1) With an increase of stress, the steady state creep rate increases and the creep rupture time decreases. 2) The steady state creep rate ε(%/s) for the stress Σsub(c) (kgf/mm super(2)) of Zr-4 increases outstandingly. All the empirical equations computed for Zr-4 increases outstandingly. All the empirical equations computed for Zr-4 are in accord with Norton's model equation(ε=KΣ sub(c) super (n)). The constants of materials computed are as follows: K=3.9881×10 super(-5), n=1.9608 3) The rupture time T sub(r) (hr) decreases linearly with the increase of stress on the log-log scaled graph. The empirical equations computed for Zr-4 are in accord with Bailey's model equation (T sub(r)=K sub(1)Σsub(c) super(m)). The constants of materials computed are as follows: K sub(1)=1.2875×10 super(16), m=-3.467 4) It seems clear that the strain could be quantitatively dependent on the high temperature creep properties such as creep stress, rupture time, steady state creep rate and total creep rate. It is found that these relationships are linear on the log-log graph. 5) In stress relaxation test, as the critical constant strain that can be allowed to the specimen is larger, stress relaxation becomes more rapid, and as the constant strain is smaller, the stress relaxation becomes slower.
This study was conducted to evaluate effects of indoor horticultural therapy program based on ‘relaxation - cognitive behavior - social support’ strategy on quality of life, stress and serotonin of woman cancer patients. Subjects were 18 female cancer patients. Experimental group of 9 members received a horticultural therapy program and control group of 9 members did not receive a horticultural therapy program. The horticultural therapy program was conducted, for 90 minutes per session, once a week, total 8 times. And this study was performed from 9. Nov. to 28. Dec. in 2015. As a results, horticultural therapy program made significant improvement in emotional condition among sub-category of quality of life, nervousness, depression and frustration among sub-category of stress. Also the program decreased the total stress score with significant increased level of serotonin comparing to control group. This result means that depression mood in cancer patients was improved. In summary, horticultural therapy program focused on indoor activities based on ‘Relaxation-social support-cognitive behavioral’ strategy could be utilized as supporting program for psychological health for cancer survivors.
스트레스는 현대 사회의 가장 큰 관심 분야로서 만병의 원인이라고 여겨지고 있다. 이러한 스트레스는 뇌파에서도 특이한 영향을 미치는데 특히, 알파파의 감소가 일어난다는 점이다. 본 연구에서는 스트레스에 관하여 EDT 기법이 뇌파중 알파파에 긍정적 영향을 미치는지 알아보기 위함에 있다. 기법의 적용은, 주 2회 10분간 2주 동안 실시하며 EDT대체의학 기법 적용이 초등학교 교사의 뇌파에 안정을 의미하는 알파파의 증가와 베타파의 감소를 보였으며, 유의한효과는 없었으나 감마파 감소에 일부 도움이 있는 것으로 사료된다. EDT 기법이 스트레스에 있어서 관련된 뇌파인 알파파에 개선에 유의한 효과가 있으므로 스트레스 관리에 적극적 활용의 필요성을 제기한다.
의료분야에 게임이 적용되는 사례가 늘고 있다. 본 게임은 게임을 즐기는 사용자의 심박동의 미세한 변화(HRV:heart rate variability)를 파형분석하여 MP(mental stress)와 PH(physical stress) 상태를 모니터링한 후 호흡(respiration)의 조절을 통해 자율신경체계의 질병을 예방하기 위한 목적으로 개발되었다. 기존의 지속적인 반복작용을 통한 단순한 트레이닝이 아닌 게임고유의 특징인 상호작용성(interaction)을 높여 사용자가 지루함이나 거부감을 느끼지 않고 접근이 용이한 스트레스이완프로그램(SRP:stress relaxation program)이라는데 의미가 있다.