• 한국지능시스템학회논문지
• /
• 제24권5호
• /
• pp.554-561
• /
• 2014

Hybrid wind Diesel stand-alone power systems are considered economically viable and effective to create balance between production and load demand in remote areas where the wind speed is considerable for electric generation, and also, electric energy is not easily available from the grid. In Wind diesel hybrid system, the wind energy system is the main constitute and diesel system forms the back up. This type of hybrid power system saves fuel cost, improves power capacity to meet the increasing demand and maintains the continuity of supply in the system. Problem we face in this system is that even after producing enough power through wind turbine system, considerable portion of this power needs to be dumped due to short term oversupply of power and to maintain the frequency within close tolerances. As a result remaining portion of total energy supplied comes from the diesel generator to overcome the temporal energy shortage. This scenario decreases the overall efficiency of hybrid power system. In this study, efficient Simulink modeling for wind-diesel hybrid system is proposed and some simulations study is carried out to verify the feasibility of the proposed scheme.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.1494-1501
• /
• 2008

Recently, the demand of water resources is constantly increasing due to the substantial increase of population, economy, and living standard. However, it is expected that the water resources should undergo serious problems of poor quality of water as well as shortage of water supply in the near future. Additionally, thoughtless groundwater development have caused to dry river and stream. In this study, the effectiveness of dry stream protection plan is evaluated by using 3-D groundwater flow modeling for the study area which is located in Namyangju of Kyoungi Province. Aquifer tests are performed to obtain the input data of the model. To analyze causes of dry stream using modeling results that water balance is analyzed for situations of before and after closing the wells.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
• /
• pp.150.2-150.2
• /
• 2013

We elucidate the mechanism of the self-assembled organic layer formation at the organic/metal interface of hexaaza-triphenylene-hexacarbonitrile (HATCN)/Au(111) by first-principles calculations and Lowtemperature scanning tunneling microscope (STM). In this work, we used HATCN to deposit organic material which is well known as an efficient OLED charge generation material. Low-temperature STM measurements revealed that self-assembled hexagonal porous structure is formed at terraces of Au(111). We also found that the hexagonal porous structure has chirality and forms only small (<1000 $nm^2$) phaseseparated chiral domains that can easily change their chiral phase in subsequence STM images at 80 K. To explain the mechanism of these observation, we calculated the molecular-molecular and molecule-surface interaction energies by using density functional theory method. We found that the change of their chiral phase resulted from the competition between the two energies. These results have not only verified our experimental observations, but also revealed the delicate balance between different interactions that caused the self-assembed structures at the surface.

• PNF and Movement
• /
• 제16권3호
• /
• pp.345-353
• /
• 2018

Purpose: The purpose of the present study was to compare the effects of proprioceptive neuromuscular facilitation (PNF) and static stretching on weight distribution and flexibility for trunk flexion. Method: Sixty participants who had no musculoskeletal disorders were recruited from a local university within six months of this study. The participants were randomly assigned to a PNF stretching group (N=30) and a static stretching group (N=32). For the pre-and post-measurement design, the left-right weight distribution, anterior-posterior weight distribution, and finger-to-floor distance (FFD) were measured before and after the stretching interventions. Result: The FFD results were significantly improved after the interventions, regardless of the group differentiation (p<0.05). The PNF stretching intervention significantly increased the differences between anterior and posterior weight distribution compared to the static stretching group (p<0.05). Conclusions: Both the PNF and static stretching interventions could improve flexibility for trunk flexion mobility. Although the PNF intervention improved the weight distribution in the anterior-posterior direction, further research is required to investigate the various PNF interventions on left-and-right and anterior-posterior weight distribution.

• 한국기계가공학회지
• /
• 제18권4호
• /
• pp.26-33
• /
• 2019

This study is a thermal and flow analysis of Organic Rankine Cycle (ORC) pipe line for 250 kW grade waste gas heat recovery. We attempted to obtain the boundary condition data through the process design of the ORC, which can produce an electric power of 250 kW through the recovery of waste heat. Then, we conducted a simulation by using STAR-CCM+ to verify the model for the pipe line stream of the 250 kW class waste heat recovery system. Based on the results of the thermal and flow analyses of each pipe line applied to the ORC system, we gained the following conclusion. The pressure was relatively increased at the pipe outside the refracted part due to the pipe shape. Moreover, the heat transfer amount of the refrigerant gas line is relatively higher than that of the liquid line.

• 한국기계가공학회지
• /
• 제18권5호
• /
• pp.90-95
• /
• 2019

This study aims to gain the design data through the process design of the organic Rankine cycle, which can produce 250kW of electric power through waste heat recovery. In this study, a simulation was conducted using APSEN HYSYS to make the model for the process design of the 250kW-class waste heat recovery system. For the thermodynamic model, the test was conducted with hot water as the heat source, the water steam as the cooling water for the cooler, and the refrigerant R245FA in the cycle. In the final design, it was expected and found from the simulation that the cycle efficiency was 12.62% and that 250kW of power was produced considering the margin of 80%.

• Nutrition Research and Practice
• /
• 제17권4호
• /
• pp.597-615
• /
• 2023

Healthy aging can be defined as an extended lifespan and health span. Nutrition has been regarded as an important factor in healthy aging, because nutrients, bioactive food components, and diets have demonstrated beneficial effects on aging hallmarks such as oxidative stress, mitochondrial function, apoptosis and autophagy, genomic stability, and immune function. Nutrition also plays a role in epigenetic regulation of gene expression, and DNA methylation is the most extensively investigated epigenetic phenomenon in aging. Interestingly, age-associated DNA methylation can be modulated by one-carbon metabolism or inhibition of DNA methyltransferases. One-carbon metabolism ultimately controls the balance between the universal methyl donor S-adenosylmethionine and the methyltransferase inhibitor S-adenosylhomocysteine. Water-soluble B-vitamins such as folate, vitamin B6, and vitamin B12 serve as coenzymes for multiple steps in one-carbon metabolism, whereas methionine, choline, betaine, and serine act as methyl donors. Thus, these one-carbon nutrients can modify age-associated DNA methylation and subsequently alter the age-associated physiologic and pathologic processes. We cannot elude aging per se but we may at least change age-associated DNA methylation, which could mitigate age-associated diseases and disorders.

• 한국환경농학회지
• /
• 제33권1호
• /
• pp.44-51
• /
• 2014

하천수질의 공간적 변이 해석에 양분 지표의 활용 가능성을 탐색하기 위해 전남 시 군의 수질 자료(T-N, T-P, BOD, COD)와 양분 지표(화학비료 공급량, 가축분뇨 발생량, 가축분뇨 양분 발생량, 양분수지)의 상관관계를 조사하였다. 수질 T-N은 화학비료 공급량, 가축분뇨 질소 발생량, 양분수지와 모두 정의 상관관계(P<0.05 또는 P<0.01)가 있었고, T-P와 이들 양분 지표와의 상관관계는 95% 수준에서 유의성이 없었지만 가축분뇨 인 발생량(P=0.06)과 양분수지(P=0.09)와는 유의미한 관계가 있었다. 따라서, 전남 지역 하천의 T-N 농도는 농경지 시용 화학비료는 물론 가축분뇨에 의해 영향을 받는 반면 T-P 농도는 화학비료 보다는 부적절한 가축분뇨처리 및 퇴비 과잉 시용에 의해 증가될 수 있음을 의미한다. 가축분뇨와 이를 원료로 제조되는 퇴비는 토양교질 및 금속이온과의 반응성이 낮아 무기태 인에 비해 상대적으로 이동성이 큰 유기태 인을 함유하고 있기 때문에 하천 T-P 농도증가에 기여할 수 있는 것으로 해석되었다. 한편, BOD와 COD는 모두 유기물질 함량이 높은 가축분뇨 발생량과 정의 상관관계(P<0.05 또는 P<0.01)가 있었는데, 이 또한 T-P의 경우와 동일하게 하천 수질에 대한 가축분뇨의 영향을 반영한다. 하지만, 본 연구에서 기상, 지형, 강우유형, 영농활동, 토지이용방식이 상이한 시 군을 대상으로 취득이 용이한 통계자료에 의존하여 양분수지를 분석하여 수질 변동을 해석한 점은 한계로 인정된다. 이와 같은 한계에도 불구하고 본 연구결과는 수질 변동 이해의 측면에서 양분 지표를 이용한 수질의 공간 변이 해석 가능성과 수질 관리의 측면에서 가축분뇨관리(폐수 처리 및 적정 퇴비 시용)의 중요성을 통계적으로 제시한다는 측면에서 의미가 있다.

• BMB Reports
• /
• 제53권8호
• /
• pp.400-412
• /
• 2020

The world has witnessed unimaginable damage from the coronavirus disease-19 (COVID-19) pandemic. Because the pandemic is growing rapidly, it is important to consider diverse treatment options to effectively treat people worldwide. Since the immune system is at the hub of the infection, it is essential to regulate the dynamic balance in order to prevent the overexaggerated immune responses that subsequently result in multiorgan damage. The use of stem cells as treatment options has gained tremendous momentum in the past decade. The revolutionary measures in science have brought to the world mesenchymal stem cells (MSCs) and MSC-derived exosomes (MSC-Exo) as therapeutic opportunities for various diseases. The MSCs and MSC-Exos have immunomodulatory functions; they can be used as therapy to strike a balance in the immune cells of patients with COVID-19. In this review, we discuss the basics of the cytokine storm in COVID-19, MSCs, and MSC-derived exosomes and the potential and stem-cell-based ongoing clinical trials for COVID-19.

• 대한물리치료과학회지
• /
• 제19권3호
• /
• pp.49-56
• /
• 2012

Background : The purpose of this study is to understand the effects of ankle joint taping on balancing abilities of the elderly and to provide preliminary data on preventing falls among the elderly. Methods : In this study, 20 students(8 male, 12 female) in their 20s from D University as well as 14 elderly(4 male, 10 female) in their 70s from S community center have participated. The participants were well informed about the experiment and voluntarily participated. We measured the difference in balancing ability before and after taping between the two groups using methods such as standing on single-leg stance, TUG, and plantar pressure. Kinesio taping, a stop-watch, and the EMED-system were used as equipment along with the SPSS 12.0 program, with a significance level of 0.05, to test the difference before and after taping between the two groups. Result : First, the 70s group showed a significant increase in the dorsal flexion angle after taping. Second, the 70s group showed a significant increase in duration time of standing on one foot after taping. Third, the 70s group's TUG time was significantly shorter. Fourth, the maximum peak value for static and dynamic plantar pressure showed a significant decrease after taping; and dynamic plantar pressure area value decreased as well within significant range. Conclusion : The study has shown that taping is effective on static dynamic balancing ability of the elderly.