• Journal of Korea Entertainment Industry Association
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• v.14 no.6
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• pp.191-199
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• 2020

Younger generations use a variety of visual media, such as smartphones, televisions, and computers. Due to the development of visual media, the health of eye was weakening. Therefore, this study aimed to investigate the effects of eye health and dynamic visual activity on eye muscle stimulation with eye movement and therapeutic massage in university students. 38 university students in their 20s were divided into a control group(18) and an experimental group(20). The experimental group performed eye movement and therapeutic massage every 30 minutes for 5 times a week for 4 weeks. Ocular fatigue, maximal blinking interval, ocular surface temperature, and dynamic visual activity were measured before and after 4 weeks. Ocular fatigue was decreased significantly after 4 weeks (p<.05), and maximal blinking interval was increased significantly after 4 weeks (p<.05). Ocular surface temperature was not showed a significant difference after 4 weeks (p>.05), and dynamic visual activity was increased significantly after 4 weeks (p<.05). Therefore, eye movement and therapeutic massage are recommended for the improvement of eye function and eye health. It is expected to be used as research data to restore and prevent for eye health.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2D
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• pp.285-292
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• 2006

The objective of this study is to introduce the development of the first Korean full-scale APT(Accelerated Pavement Tester) and to compare the performances of general dense grade asphalt mixture and modified asphalt mixtures as the first running of the tester. The tests evaluated the rutting resistance for dense grade mixture and three different modified asphalt mixture under three different temperature conditions (25-30, 40, $50^{\circ}C$). The results of the testing were compared with the laboratory test results. Results of the tests indicated that the all the modified asphalt sections showed higher rutting resistance than the dense grade section. Especially, the difference was more noticeable at higher temperature condition. Additionally, $G^*/sin{\delta}$ is found out to be an important factor for permanent deformation prediction whereas the resilient modulus was not.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.2
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• pp.163-170
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• 2016

The purpose of this study was to verify the emotional response of user to LED light colors in healing bed system in cypress tree. Eight colors of LED light were provided including red, orange, yellow, green, blue, indigo, violet and white. And three illumination color temperature were provided including 3,000K, 5,000K, 8,000K. Seven subjects in their twenties were involved without the medical history of eyes and heart disorders. The subjects were exposed to LED lighting during 5 minutes and their emotional response was evaluated through the following: first, at the physiological effect heart rate variability(HRV) was measured during the stimulation; second, at the emotion level the subjects were asked about lighting color and color temperature through a survey. Results, lower color temperature of 3,000K and green color shows high value on HRV. We have found that there is a difference of physiological and emotion level effect depending on color stimulus. This study could be applied to reference data to analysis of a decrease in fatique and charges of brain waves for color stimulus.

• Korean Journal of Materials Research
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• v.4 no.5
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• pp.524-534
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• 1994

The effects of transformation temperature and mechanical properties by thermal cycle of CuZnAl shape memory alloy with a small of misch metal and Zr contents were investigated. The addition of misch metal and Zr was very effective for reducing the grain size. After solution treatment, the specimens were post-quench aged or step quenched at $100^{\circ}C$ to $350^{\circ}C$ for variation of Rockwell hardness value. It was found that the Rockwell hareness value was very increased at $200^{\circ}C$ and $250^{\circ}C$. The fracture strength and ductility have been significantly increased with the increase of misch metal conten when tensile tested below $M_f$ temperature. Also, the fracture strength has been more increased in the case of post quench aging treatment than that of the as-quenching treatment. Aging of the $\beta$-phase decreases the $M_s$ temperature, but that of the martensite phase increases the $A_s$ temperature. The change in $A_s$ temperature with post-quench aging can be attributed to recovery of order in the $\beta$phase. The hystersis of transformation temperature ($A_s-M_s$) has an increasing tendency by thermal cycles.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.4
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• pp.289-298
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• 2014

Purpose: This study was designed to investigate the present conditions of illumination techniques in dental laboratories in order to distinguish colors for esthetic dentistry. Materials and Methods: A total of forty-eight local dental laboratories were selected for sampling a) luminous intensity and b) color temperature. We measured the luminous intensity and the color temperature on a center point of porcelain table with lux meter and color meter respectively. The measurements were performed twice, once on a clear day and on a cloudy day between 12 pm and 2 pm (day light and artificial illumination) and between 7 pm and 10 pm (artificial illumination only). Results: The results obtained were as follows. 1. The average luminous intensity in dental laboratories lighting was 1871 lx, and 67% of dental laboratories had luminous intensity greater than 1600 lx, which was appropriate for operations related to colors, while 33% of dental laboratories had in sufficient lighting for appropriate luminous intensity. 2. The average color temperature in dental laboratories lighting was 6506 K, which was inappropriate for operations related to color. None of the dental laboratories had a color temperature range of 5000 - 5500 K, which is appropriate for operations related to colors. 3. Between daytime and nighttime, also between clear day and cloudy day, the average luminous intensity and color temperature in dental laboratories were not significantly different. Conclusion: Illumination in most dental laboratories selected in this study was inappropriate for operations related to color.

• Landscaping Tree
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• s.127
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• pp.37-40
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• 2012

지난 호의 소나무류 가지마름성 병해에 이어 이번 호에서는 소나무류 잎마름성 병해를 소개한다. 소나무의 잎에서 나타나는 잎마름성 병해는 증상과 원인이 다양하여 정확한 원인을 밝히기가 매우 어렵다. 그 이유는 수목의 이상 증상은 기본적으로 1) 비기생성(생리적, 비점염성) 원인, 2) 기생성(생물적, 전염성) 원인에 의하여 발생하는데, 진단 결과에 따라 수목의 재배환경을 점검하고 개선하여야 할 문제인가(비기생성 원인), 또는 약제를 사용하여야 할 것인가(기생성 원인)를 먼저 결정하여야 한다. 그 이유는 피해 원인이 물, 온도, 제초제 등 비기생성 원인에 의한 것이라면 재배환경의 개선 또는 원인 제거만으로도 충분히 나무를 회복시킬 수 있고, 병원균에 의한 것이라면 정확한 병명 진단 후에 적용 약제를 적절한 시기에 살포하여 불필요한 농약의 사용을 줄이면서 효과적으로 방제할 수 있기 때문이다. 수목의 잎에서 흔히 나타나는 이상 증상은 다음과 같이 비기생성 원인과 기생성 원인을 포함하여 크게 세 가지로 구별할 수 있으며, 기본적인 진단 요령과 원인은 다음과 같다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.9
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• pp.2271-2279
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• 1993

In the case of life prediction on the structures and machines after long service, it is natural to consider a degradation problems. Most of degradation data form practical structures are isolated data obtained at the time of periodical inspection or repair. From such data, it may be difficult to obtain the degradation curve available and necessary for life prediction. In this paper, for the purpose of obtaining a degradation curves, developed the simulate degradation method and fatigue test and Charpy impact test were conducted on the degraded, simulate degraded and recovered materials. Fatigue life prediction were conducted by using the relationship between fracture transition temperature (DBTT : vTrs) obtained from the Charpy impact test through the degradation process and fatigue crack growth constants of m and C obtained from the fatigue test.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.3
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• pp.171-178
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• 2002

본 연구의 목적은 순수 티타늄에 열처리를 통해 서로 다른 두께의 산화막을 형성하여 온도차이에 따른 골결합에 대한 영향을 관찰하고자 하는 것이다. 총 52개의 임플란트를 제작하여 열처리를 하지 않은 26개의 임플란트를 대조군으로, $600^{\circ}F(316^{\circ}C)$에서 10분간 열처리한 13개의 임플란트를 실험군 1로, $1200^{\circ}F(649^{\circ}C)$에서 10분간 열처리한 13개의 임플란트를 실험군 2로 하여 13마리의 가토의 경골에 식립한 후 12주 후의 removal torque를 측정 비교함으로써 다음과 같은 결과를 얻었다. 1. 실험군 2에서는 결정구조가 생성된 것이 관찰되었으나, 실험군 1에서는 무정형이었다. 2. 대조군에 비해 열처리를 한 실험군들이 더 큰 removal torque 값을 나타냈다(p=0.0059, 0.0039). 3. 실험군 2가 실험군 1에 비해 큰 removal torque 값을 나타냈다(p=0.0488).

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.521.1-521
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• 1986

B. sphaericus의 sporeless ts-D1216 돌연변이체의 유전학적 특성을 방사성 동위원소를 이용하여 DNA의 합성과 RNA의 합성을 측정하였고 일반적 특성을 연구하였다. ts-D1216 돌연변이체의 대수증식기 세포를 3$0^{\circ}C$에서 제한온도 (42$^{\circ}C$)로 이동시켰을 때 RNA의 합성은 4-5시간 정상적으로 합성이 계속 일어났고, DNA의 합성은 60-100분까지는 정상적인 율로 일어나다가 그 후에 결정적으로 감소되었다. 또한, DNA합성이 멈춘후에도 세포수는 증가했고, 4$0^{\circ}C$에서 성장기간이 더 길면 길수록 DNA합성에의 회복능력이 상실되었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.57.2-57.2
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• 2011

MX 석출물 형성 원소인 V과 Nb을 첨가한 11Cr-1Mo-VNb 페라이트계 내열강의 각각의 시험 온도에서 파단 시간에 따른 미세조직의 변화를 연구하였다. 초기 조직은 템퍼드 마르텐사이트 조직을 갖고 있었으며, 고온 강도를 저하시키는 ${\delta}$-페라이트는 존재하지 않았다. 주 석출상은 $M_{23}C_6$와 MX로 확인되었다. 또한, 모든 크리프 파단재에서 응력을 받은 게이지 부분이 응력을 받지 않은 그립 부분보다 석출물 및 마르텐사이트 래스 폭의 성장이 가속되는 결과를 나타내었다. 이는 크리프 변형 중 응력 집중에 의해 래스 경계를 따라 전위가 집적되고, 이에 따른 용질원자의 확산 속도가 증가하여 석출물의 성장에 따른 래스 경계의 이동이 일어나 게이지 부분이 그립 부분보다 마르텐사이트 회복이 가속된 것으로 판단된다.