• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.247-258
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• 2008

In this study, static loading tests were performed on H-beam specimens to assess the static behavior of H-beam prestressed with multi-stepwise thermal prestressing method (TPSM). The amount of induced thermal prestress and connection type were differentiated among the 400-mm-high and 6,000-mm-long H-beam specimens to evaluate their effect on the behavior of the beams. From the experimental results, it between the H-beam and the cover-plate increased in yielding load by 13~18%, whereas stiffness increased by 27~34%. In case of specimens with both bolting and welding connection, yie lding load increased by 18~29% and stiffness increased by 43~51%. Multi-stepwise initial stress distribution was also observed from the prestressed specimens, verifying the effectiveness of the multi-stepwise TPSM. By application of the multi-stepwise TPSM, a significant increase in yielding load and stiffness can be achieved, hence increasing sectional and prestressing efficiencies.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.2
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• pp.55-61
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• 2008

This paper shows quantitative reliability evaluations of a Bluetooth module through extending previous qualitative methods limited to structure reliability tests and solder joint reliability tests for Bluetooth modules. Accelerated Life Testing (ALT) of the modules using temperature difference in temperature cycling as an accelerated stress was conducted for quantitative reliability evaluation under field environment conditions. Lifetime distribution parameters were estimated using the failure times obtained through the ALT, and then Coffin-Manson model was implemented. Results of the ALT showed that the failure mode of the modules was open and the failure mechanisms are both crack and delamination. The ALT reproduced the failure mode and mechanisms of failed Bluetooth modules collected from the field. Further, a quantitative reliability evaluation method with respect to various temperature differences in temperature cycling was proposed in this paper. $B_{10}$ lifetime of the module for the temperature difference $70^{\circ}C$ using the proposed method would be estimated as about 4 years.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.46-53
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• 2016

LED light sources have been known to have a long life and good energy efficiency compared to traditional light sources. Recently, headlamps using LED light sources have ensured the forward visibility and safe operation of high-speed rolling stock. However, assessing the lifespan of LED headlamps based on real test data is not easy because it depends on the multiple stress factors such as a fixed driving current, junction temperature, vibration and so on. Generally, LED headlamps have failed before their advertised life span mainly due to temperature. Thus, the performance assessment of a temperature control unit should be done before a life cycle test of LED headlamps. This study attempted to develop a prototype temperature control module for a lifecycle test system using a commercial LED headlight and verified the system through experiments.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.261-268
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• 2017

The study is designed to explore the effects of the Acceptance-Commitment Therapy (ACT) on Reserve Officer's Training Corps (ROTC)' stress, anxiety, and acceptance. Among the total of 82 ROTC, total of 12 participants whom showed over-average scores for stress and anxiety and agreed to participate in study were selected. The ACT group received twice-weekly, approximately 90 minute, total of 8 sessions of ACT program Both groups filled out Perceived Stress Scale, State-Trait Anxiety Inventory, and Acceptance and Action Questionnaire each before, at the end of, and 4 weeks after the program. The result showed that the group that participated in ACT program showed significant decrease in stress and anxiety, and although the overall acceptance behavior showed no significant change, the Acceptance - a subfactor of the scale - showed significant increase. This study suggest empirical evidence to prove that the ACT is effective in reducing stess and anxiety of ROTC. However, the study has only few ROTC participants and thus has limitations. Therefore it is crucial that future studies are conducted addressing this issue.

• Journal of Sensor Science and Technology
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• v.4 no.3
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• pp.51-59
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• 1995

Stress-balanced flat 150 nm-$Si_{3}N_{4}$/300 nm-$SiO_{2}$/150 nm-$Si_{3}N_{4}$ dielectric membrane on silicon substrate has been fabricated. Analyses of stress-deflection and stress-temperature, and visual inspection for the strain diagnostic test patterns were performed in order to characterize stress properties of the membrane. The $SiO_{2}$ layers sandwiched between two $Si_{3}N_{4}$ layers were deposited by three different techniques(PECVD, LPCVD, and APCVD) for the purpose of investigating the dependence of stress on the deposition methods. Some extent of tensile stress in the membrane was always observed regardless of the deposition methods, however it could be balanced against silicon substrate by post-wet oxidation in $1,150^{\circ}C$. Stress-temperature characteristics of the membranes showed that APCVD-LTO was better as mid-$SiO_{2}$ layer than PECVD - or LPCVD - $SiO_{2}$ when there was no oxidation process.

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.810-820
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• 2016

This study is focused on the investigation of the genes which are induced by various stresses of the halophyte Salicornia herbacea. One of the factors influencing in the germination of Salicornia herbacea is salt stress. The highest germination rate was found in the condition without NaCl, and the upper limit of the NaCl concentration for the germination of Salicornia herbacea was 7%. The optimal temperature of $20^{\circ}C$showed a germination rate of 98%. Among genes induced by stress the 2CysPrx gene was cloned and analyzed for this study. The 2CysPrx gene has two cysteine conserved residues and is composed of 275 amino acids with molecular weight of 30.1kDa. The 2CysPrx gene appeared to be one copy in the genome and consists of 6 introns and 7 exons. Quantitative real-time PCR revealed that the highest transcription rate induced by NaCl and $H_2O_2$ appeared to be at the concentration of 3.5% NaCl and 40mM $H_2O_2$, respectively. The amount of transcript induced by high temperature($40^{\circ}C$) and $75{\mu}M$ of ABA was respectively highest. The gene at low temperature ($4^{\circ}C$) appeared not to be expressed. We are conducting to clone other peroxyredoxin genes induced by various environmental stresses.

• 건강소식
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• v.15 no.8 s.153
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• pp.2-5
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• 1991

바쁜 현대인. 그들에겐 즐거운 취미활동이나 건강을 위한 운동을 할수 있는 시간보다는 스트레스에 쌓여야 하는 시간이 더 많다. 그러나 이런 정신없는 틈을 타 예술활동을 하면서 건강도 도모하는 모임이 있다. "대한 사진예술가협회" 50년 가까이 한국사진계의 맥을 이어온 대한사진예술가협회는 사진을 통한 자기발견과 정기출사를 통한 건강관리를 사람들에게 권하고 있다. 전문 직업인은 아니지만 누구보다 사진예술에 관한 애착을 가지고있고 그만큼의 실력을 이어오고 있는 협회를 찾아가 봤다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.610-611
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• 2001

연안 및 조간대에 서식하고 있는 정착성이거나 이동이 적은 패류들은 조석주기와 분포 등에 의해 일정한 주기로 공기 노출에 직면하고 있으므로 이러한 생물들은 먹이를 섭취하는 시간에 제한을 받으며, 온도의 변화 및 건조에 스트레스를 받고 있다. 공기노출시 패류의 생리적 반응은 종에 따라 다르게 나타나며, 전형적으로 패각을 닫는 형태와 패각을 여는 형태로 나누어지며, 일반적으로 공기에 노출된 후 다시 물에 잠김에 따라 빠르게 대사를 회복시킨다. (중략)

• Journal of agriculture & life science
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• v.53 no.2
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• pp.121-129
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• 2019

This study carried out to determine control factors for the improvement of productivity of laying hens suffering heat stress during hot weather. A total of 48,451 ISA Brown layers were housed in a farm located in Gyeongsangnam-do, Republic of Korea. Five thermo-hydrometer loggers were installed inside the house to collect data of dry-bulb temperature and relative humidity. The experiment continued for 81 days when the summer season begins from 19th June to 7th September, 2018. This study analyzed the correlations among layers' production index and daily average, highest, and lowest temperature; daily average, highest, and lowest relative humidity; and daily average, minimum, and maximum THI. The result indicated that feed consumption, hen-day egg production, egg weight, and FCR decreased as the daily average, highest and lowest dry-bulb temperature and THI rise (p<0.01). On the other hand, water intake increased as the daily average, highest and lowest dry-bulb temperature and THI rise (p<0.001). The relative humidity was not considered to have direct correlations to the layers' production index (p>0.05). However, it was noticeable that the mortality did not have significant relations with daily average and highest temperature; THI; or daily average, highest and lowest relative humidity while it was relevant to the daily lowest temperature and THI (p<0.05). In conclusion, to enhance the productivity of laying hens in a hot climate, it is recommended that daily average, highest, and lowest dry-bulb temperature and THI are maintained as low as possible. Especially, the daily lowest temperature is needed to lower to 20℃, which is the lowest critical temperature for layers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.10
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• pp.641-646
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• 2016

Coil specimen was prepared by coating a copper wire with two varnish thin layers: the first was polyamideimide (PAI)/nanosilica (5 wt%) varnish and the second was anti-corona PAI/nanosilica (15 wt%) varnish. Insulation breakdown voltage was investigated under inverter surge condition at $20^{\circ}C$, $70^{\circ}C$, $100^{\circ}C$, $150^{\circ}C$, $200^{\circ}C$, $250^{\circ}C$, respectively. The insulation lifetime of the two layered coil was tens of times longer than that of original PAI coil. And the insulation lifetime decreased with increasing ambient temperature because there was weak binding strength between copper and varnish layer.