• 대한인간공학회지
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• 제28권4호
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• pp.91-99
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• 2009

A visual stress may provoke migraine, cephalalgia, intervene a long term reading and learning capability and reduce the productivity of a laborer who uses computer for a good while. In this study, a web based screening tool for visual stress was developed, it applied to 72 visually normal young persons in parallel with traditional questionnaire about symptoms of visual stress. To estimate visual stress, It is proposed to measure difference of visual search time of Han Gul characters as targets between visual stressful pattern and non-visual stressful pattern as global background of characters. As a result of test, 5 subjects were screened whose mean visual search time in the stressful pattern with 6 CPD spatial frequency increase significantly more than in none stressful pattern(t-test, one-tailed, p=$1.0407\times10^{-11}$). 2 of them were diagnosed as mild visual stress syndrome in the clinic. None had visual distortion and 50% of subjects had visual discomfort in results of the questionnaire. Correlation between visual search time increase rate and normalized number of visual discomfort may be slight(C. coefficient=0.1355). This study may contribute as a basic research for screening person with migraine, visual reading disabilities and VDT syndrome. It is required to apply the test to visual reading disabilities, migraine with visual distortion and/or visual discomfort as well as normal person for higher reliability of the screening tool.

• 생명과학회지
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• 제9권5호
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• pp.548-555
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• 1999

Long-term effects of Ganoderma lucidum (GL) on memory and oxidative stress of senescence-accelerated mice (SAM) were investigated. Senescence-resistant (R1) and prone (P8) strains of SAM were fed GL diets, premixed with low (20 mg/kg/day, T1) or high (200 mg/kg/day, T2) levels of GL powder for 9 months starting from young (3 months of age) or for 5 months starting from old (7 months of age). After the final feeding at 12 months of age, all animals were subjected to passive avoidance test for the evaluation of memory function. In addition, the changes in hepatic thiobarbituric acid-reactive substance (TBARS) and glutathione were analyzed. SAMP8 fed GL diets from old age (7 months) exhibited the improvement of memory, although GL rather inhibited the memory function of both SAMR1 and SAMP8 mice fed diets from young (3 months of age). Hepatic TBARS contents were decreased in SAMP8 fed high GL diet for 9 months and in SAMR1 fed low GL diet for 5 months. Hepatic glutathione content was also remarkably increased in SAMR1 following both feeding periods, and less extent in SAMP8 fed diet for 5 months of age. Taken together, it is proposed that GL extracts may play an anti-aging role through antioxidant action, and thereby may improve the senescence-related memory dysfunction.

• 한국콘텐츠학회논문지
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• 제9권9호
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• pp.325-334
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• 2009

본 연구의 목적은 민간경비원의 여가활동과 직무스트레스 및 이직의사의 관계를 규명하는데 있다. 이 연구는 수도권 소재 민간경비 회사에 재직하고 있는 민간경비원을 대상으로 설정 하였으며, 판단표집법을 활용하여 총 360명을 표집 하였다. 그러나 최종 분석에 사용된 사례 수는 333명이다. 연구에 이용된 설문지의 신뢰도는 $\alpha$=.752 이상으로 나타났다. 수집된 자료는 SPSSWIN 16.0을 이용하여 요인분석, 신뢰도분석, t검증, F검증, 다중회귀분석, 경로분석 등의 방법을 활용하였다. 결론은 다음과 같다. 첫째, 사회인구통 계학적 특성에 따라 직무스트레스 및 이직의사는 차이가 있다. 둘째, 여가활동 참가기간은 신체적 스트레스에 영향을 미친다. 즉, 여가활동 기간이 증가하면 직무스트레스는 감소한다. 셋째, 여가활동 참가정도는 이직의사에 영향을 미치지 않는다. 넷째, 여가활동 참가는 직무스트레스 및 이직의사에 인과적 영향을 미친다. 즉, 직무스트레스는 여가활동과 이직의사의 관계를 매개하는 중요한 변수이다.

• 동력기계공학회지
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• 제16권1호
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• pp.58-64
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• 2012

Power plant boiler is one of the most important utilities providing steam to turbine in thermal power plant. It is composed of thousands of boiler tubes for high efficient heat transfer. Boiler tube material is used in such high temperature and pressure as $540^{\circ}C$, $170kg/mm^2$. The boiler tube material is needed to resist corrosion damage, creep damage and fatigue damage. 2.25%Cr-1Mo steel is used for conventional boiler tubes. In these days steam temperature and pressure of the power plant became higher for high plant efficiency. So, the material property of boiler tube must be upgraded to meet the plant property. Several boiler tube material was developed to meet such condition. X20CrMoV12.1 steel is also developed in early 1980's and used for superheater and reheater tubes in supercritical boilers. The material has martensitic structure, which is difficult to evaluate the material degradation. Boiler tube material at severe condition was tested to evaluate long term and short term degradation and creep. Through long term and high temperature degradation test, lath structure was decreased and recrystallization has been proceeded by sub-crystal. And in this research the effect of temperature and stress on boiler tube characteristic,for example, deformation by creep was changed rapidly at relatively high temperature and stress because creep was affected easily by temperature and stress.

• 대한통합의학회지
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• 제9권3호
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• pp.19-35
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• 2021

Purpose : Recently, there has been a growing social interest in aging well. Consequently, wellness tourism has begun to attract attention. However, no studies on whether wellness tourism has any objective health benefits have been carried out yet. In this study, we assess the health benefits as well as the degree of improvement in health of a wellness tourism program. Methods : The study involved 30 adults over the age of 19 who live in the Gyeongsangnam-do region. Participants were evaluated on health indicator before and after participating in wellness tourism program. Participants took heart rate variability (HRV) test, and LFT, RFT, CBC, FBS HbA1C, and CRP test were conducted before and after the tour. Additionally, a survey was conducted before and after the program, and participant satisfaction was evaluated. Statistical differences in the tests conducted before and after the program were analyzed using a design t-test, a Wilcoxon signed-rank test, and McNemar's test. Results : The study showed that participants were very satisfied with and had significant health improvements after the wellness tourism program. The program was also found to be beneficial in improving participants' emotions as follows: BDI (p<.001), fatigue recovery (p=.006), stress relief (p=.003), improved quality of life (p<.05), and improved sleep quality (p<.001). Conclusion : Wellness tourism programs are specifically beneficial for improving participants' emotions (depression, anxiety), fatigue, stress levels, quality of life, and sleep. Therefore, they are beneficial to the overall health. Further research in the future by way of a follow-up study on the long-term effects on health after short-term interventions will provide more validation data.

• Corrosion Science and Technology
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• 제5권2호
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• pp.69-76
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• 2006

Premature cracking of the epoxy coatings applied on ship's ballast tanks(BT) can lead to damage of ship's hulls. To avoid this, it's important to have clear understanding of the underlying mechanism and primary factors of the coating crack. In this study, the efforts were made to clarify the integrated effects of main factors, i.e., initial coating shrinkage, thermally induced strain, steel-structural strain and the intrinsic coating flexibility at the initial and after aging, to the early cracking phenomena of epoxy coating in the ship's ballast tank. The coating crack is caused by combination of thermal stress, structural stress, and internal stresses which is closely related to chemical structures of the coatings. On the other hand, thermal stresses and dimensional stabilities would rarely play a major role in coating crack for ballast tank coatings with rather large flexibility. Crack resistance of the coatings at early stages can be estimated roughly by measuring internal stress, FT-IR and $T_g$ value of the coatings. A new screening test method was also proposed in this study, which can be possibly related to the long-term resistance of epoxy-based paints to cracking.

• 한국해양공학회지
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• 제22권6호
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• pp.58-63
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• 2008

The short-term high temperature creep rupture behavior of Ni-based Alloy718 steels jointed by friction welding wasinvestigated at the elevated temperatures of 550 to $700^{\circ}C$ under constant stress conditions. The creep rupture characteristics such as creep stress, rupture time, steady state creep rate, and initial strain were evaluated. Creep stress has a quantitative correlation between creep rupture time and steady state creep rate. The stress exponents (n, m) of the experimental data at 550, 600, 650 and $700^{\circ}C$ were derived as 26.1, -22.4, 22.5, -18.5, 17.4, -14.3 and 6.9, -8.1, respectively. The stress exponents decreased with increasing creep temperature. The creep life prediction was derived by the Larson-Miller parameter (LMP) method and the result equation obtained is as follows: T(logtr+20)=-0.00148${\sigma}^2$-3.089${\sigma}$+23232. Finally, the results were compared with those of the base metal for Alloy718.

• 디지털융복합연구
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• 제18권11호
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• pp.273-283
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• 2020

본 연구는 요양병원 간호사의 임상수행능력의 긍정적인 효과를 높이기 위한 교육자료구성의 기초자료로 활용하고자 시도되었다. G도에 소재한 요양병원 간호사 166명을 대상으로 자료수집 하였다. IBM SPSS WIN/21.0을 이용하여 t-test, ANOVA, Pearson correlation coefficient, Multiple regression을 사용하였다. 대상자의 임상수행능력은 죽음인식과 순상관관계가 있었다(r=.28, p<.001). 대상자의 임상수행능력에 가장 영향을 미치는 요인은 죽음인식(β=.235, p=.002)이었고, 다음으로 기혼(β=-.214, p=.004), 희망일 휴무 '그렇다' (β=-.182, p=.013)이며, 설명력은 16.2%이었다(F=10.528, p<.001). 본 연구결과로 미루어 볼 때, 요양병원 간호사의 임상수행능력을 높이기 위해서는 죽음인식을 높여줄 수 있는 교육이 필요하며, 근무시 희망휴무가 가능하도록 배려하며, 기혼자의 근무를 장려할 필요가 있다. 이 결과를 바탕으로 요양병원의 간호사 근무스케줄 배정 및 조정에 활용할 수 있을 것이며, 임상수행능력 향상을 위한 기초자료로 활용될 것이라 기대한다.

• 한국해양공학회지
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• 제22권6호
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• pp.52-57
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• 2008

The short-term high temperature creep rupture behavior of Ni-based Alloy718 steel was investigated at the elevated temperatures range of 550 to $700^{\circ}C$ under constant stress conditions. The creep rupture characteristics such as creep stress, rupture time, steady state creep rate, and initial strain were evaluated. Creep stress has a quantitative correlation between creep rupture tim and steady state creep rate. The stress exponents (n, m) of the experimental data at 550, 600, 650 and $700^{\circ}C$ were derived as 33.5, -24.9, 26.1, -21.2, 16.8, -12.8 and 10, -8.2, respectively. The stress exponent decreased with increasing creep temperature. The creep lift prediction was derived by the Larson-Miller parameter (LMP) method and the resultant equation was obtained as follows: T($logt_r$+20)=-0.00252 ${\sigma}^2$-1.377${\sigma}$+-22718.

• 한국노년학
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• 제39권4호
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• pp.903-920
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• 2019

본 연구는 요양병원 간호사의 간호행위 위임정도, 간호전문직관 및 이직의도를 파악하고 이들간의 관계를 확인함으로써 향후 간호행위 위임에 필요한 정책적 지침 및 절차에 관한 기초자료를 제공하고자 시도되었다. 본 연구는 서술적 조사연구로 구조화된 설문지를 이용하여 2개 광역도 소재 6개 요양병원의 간호사 146명을 대상으로 실시하였으며, 자료수집기간은 2016년 7월부터 8월까지이었다. 수집된 자료는 SPSS 22.0을 이용하여 기술통계, t-test, ANOVA, Pearson 상관분석을 실시하였다. 연구결과, 요양병원 간호사의 간호행위는 위임에 대한 명확한 지침이나 법적 절차가 없는 상태에서 7개 행위를 제외한 대부분의 간호행위가 간호보조인력에게 위임되고 있었다. 요양병원 간호사의 간호행위 위임정도와 간호전문직관, 이직의도와의 유의한 관련성은 없었으나 간호전문직관과 이직의도는 유의한 음의 상관관계를 보였다. 따라서, 요양병원 간호사의 이직의도를 낮추기 위해서는 개인적인 측면으로 긍정적인 간호전문직관을 확고히 하는 방안이 모색되어야 하며, 정책적인 측면에서는 요양병원의 적절한 간호인력배치 기준을 마련하여 간호행위 위임지침을 개발해야 한다.