• BMB Reports
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• 제56권12호
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• pp.645-650
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• 2023

Numerous studies have investigated the cellular prion protein (PrP^C) since its discovery. These investigations have explained that its structure is predominantly composed of alpha helices and short beta sheet segments, and when its abnormal scrapie isoform (PrPSc) is infected, PrPSc transforms the PrP^C, leading to prion diseases, including Creutzfeldt-Jakob disease in humans and bovine spongiform encephalopathy in cattle. Given its ubiquitous distribution across a variety of cellular types, the PrP^C manifests a diverse range of biological functions, including cell-cell adhesion, neuroprotection, signalings, and oxidative stress response. PrP^C is also expressed in immune tissues, and its functions in these tissues include the activation of immune cells and the formation of secondary lymphoid tissues, such as the spleen and lymph nodes. Moreover, high expression of PrP^C in immune cells plays a crucial role in the pathogenesis of prion diseases. In addition, it affects inflammation and the development and progression of cancer via various mechanisms. In this review, we discuss the studies on the role of PrP^C from various immunological perspectives.

• 한국전산유체공학회지
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• 제15권2호
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• pp.41-46
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• 2010

In this paper, the fluid dynamic forces and performances of a moving airfoil in the low Reynolds number flow is addressed. In order to simulate the necessary propulsive force for the moving airfoil in a low Reynolds number flow, a lattice-Boltzmann method is used. The critical Reynolds and Strouhal numbers for the thrust generation are investigated for the four propulsion types. It was found that the Normal P&D type produces the largest thrust with the highest efficiency among the investigated types. The leading edge of the airfoil has an effect of deciding the force production types, whereas the trailing edge of the airfoil plays an important role in augmenting or reducing the instability produced by the leading edge oscillation. It is believed that present results can be used to decide the optimal propulsion types for the given Reynolds number flow.

• 한국전산유체공학회지
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• 제8권2호
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• pp.24-32
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• 2003

In this work, we propose a new idea of flapping airfoil design for optimal aerodynamic performance from detailed computational investigations of flow physics. Generally, flapping motion which is combined with pitching and plunging motion of airfoil, leads to complex flow features such as leading edge separation and vortex street. As it is well known, the mechanism of thrust generation of flapping airfoil is based on inverse Karman-vortex street. This vortex street induces jet-like flow field at the rear region of trailing edge and then generates thrust. The leading edge separation vortex can also play an important role with its aerodynamic performances. The flapping airfoil introduces an alternative propulsive way instead of the current inefficient propulsive system such as a propeller in the low Reynolds number flow. Thrust coefficient and propulsive efficiency are the two major parameters in the design of flapping airfoil as propulsive system. Through numerous computations, we found the specific physical flow phenomenon which governed the aerodynamic characteristics in flapping airfoil. Based on this physical insight, we could come up with a new kind of airfoil of tadpole-shaped and more enhanced aerodynamic performance.

• 한국자동차공학회논문집
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• 제20권3호
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• pp.126-132
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• 2012

Recently, pedestrian protection related research topics have been actively studied by automotive designers and engineers due to the enhanced pedestrian protecting regulations. It is required to design an energy absorbing structure, such as crumple zone that can sufficiently absorb the impact energy to reduce the leg injury when accident happens. The structure is designed by reducing the height of front end module, considering the mounting location, and investigating impact characteristics. In this paper, the concept of the crumple zone was introduced and the role of the crumple zone was investigated by analyzing the performance of upper legform impact to a bonnet leading edge test, and the design process was suggested.

• 한국재료학회지
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• 제15권5호
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• pp.313-317
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• 2005

The relation between bulk microdefect (BMD) and mechanical strength of $P/P^-$ epitaxial silicon wafers (Epitaxial wafer) as a function of nitrogen concentrations was studied. After 2 step anneal$(800^{\circ}C/4hrs+1000^{\circ}C/16hrs)$, BMD was not observed in nitrogen undoped epitaxial silicon wafer while BMD existed and increased up to $3.83\times10^5\;ea/cm^2$ by addition of $1.04\times10^{14}\;atoms/cm^3$ nitrogen doping. The slip occurred for nitrogen undoped and low level nitrogen doped epitaxial wafers. However, there was no slip occurrence above $7.37\times10^{13}\;atoms/cm^3$ nitrogen doped epitaxial wafer. Mechanical strength was improved from 40 to 57 MPa as nitrogen concentrations were increased. Therefore, the nitrogen doping in silicon wafer plays an important role to improve BMD density, slip occurrence and mechanical strength of the epitaxial silicon wafers.

• 유통과학연구
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• 제16권10호
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• pp.5-21
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• 2018

Purpose - This case study reviews the development history of Lotte Shopping, which has played a key role in modernizing Korea's retail industry. Research design, data, and methodology - Lotte Shopping's expansion to various channel types has been reviewed from the perspective of the resource-based view of strategy. The opening of Lotte Department Store in 1979 signaled the beginning of the modernized distribution system in Korea. Lotte Shopping expanded its business domains to various types of retail channels, such as discount stores, online shopping malls, TV home shopping, convenience stores, supermarkets, home appliances specialty stores and health & beauty stores. Results - Lotte Shopping has been able to maintain high level of customer satisfaction with leading merchandising skills. It has developed mutually beneficial relationship with the partner firms. It has also been a leading firm in implementing corporate social responsibility activities and environment-friendly management. Lotte Shopping has applied advanced information and communication technology to provide customized goods/services. Conclusions - This study summarizes the business environment and new challenges Lotte Shopping faces currently. Lotte Shopping is trying to reinforce the omni-channel strategy, which can create synergy among various distribution channels based on its core competences.

• Journal of Acupuncture Research
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• 제15권2호
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• pp.437-454
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• 1998

Osteopotosis is a disease characterized by reduced amount of bone mass leading to enhanced bone flagility. The number of patients with osteoporotic vertebral fracture is increasing and it is one of the leading causes of morbidity in the elderly and postmenopausal women. It is a condition in which bone mass decrease, causing bones to be more susceptible to fracture. A trivial trauma can easily cause one or more bones to break in a person with severe osteoporosis. So it is a major health problem. Pysicians and patients are concerned with the optimum approach to the treatment and prevention of osteoporosis. Until a recent date, many oriental medicine studies were performed to find the preventive and curative efficacy on the osteoporosis, which is differ from therapeutics of Western-medicine. The proper use of Herb-med and role of Accupuncture are issues that have generated major research efforts. This study was carried out to investigate evaluation of clinical and experimental study on the osteoporosis. So, these are to be mentioned in this paper.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.30-35
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• 2001

To get higher efficiency of gas turbine, The designer should have more higher turbine inlet temperature (TIT). Today, modem gas turbine having sophisticated cooling scheme has TIT above $1,700^{\circ}C$. In the korea, many gas turbine having TIT above $1,300^{\circ}C$ was imported and being operated, but the gas with high TIT above $1,300^{\circ}C$ in the turbine will give damage to liner of combustor, and blade of turbine and etc. So frequently maintenance for parts enduring high temperature was performed. In this study, the heat transfer analysis of cooling air in the internal cooling channel (network analysis) and temperature analysis of the blade (Finite Element Analysis) in the first stage rotor was conducted for development of the optimal cooling passage design procedure. The results of network analysis and FEM analysis of blade show that the high temperature spot are occured at the leading edge, trailing edge near tip, and platform. so to get more reliable performance of gas turbine, the more efficient cooling method should be applied at the leading edge and tip section. and the thermal barrier coating on the blade surface has important role in cooling blade.

• 품질경영학회지
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• 제40권3호
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• pp.372-380
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• 2012

Purpose: The purpose of this research is to develop the methods for evaluating the business value of a company's technical portfolios. In this study, technical portfolios of 10 major manufacturers and e-Biz industries are examined first from a business model perspective. Subsequently, we suggest future direction of R&D for the pharmaceutical industry by deducing the leading industries sharing similar traits with the pharmaceutical industry. Methods: In order to evaluate and analyze the patents of the major leading industries based on the constituents of a business model, the target patents were selected through the following procedure. Results: First, In this study, using the data obtained from the patent analysis, the differences in the technology portfolios of specific business entities based on the constituents of their business models. Second, deduced business rules of particular business entities through classification analysis and role-model of pharmaceutical industry Conclusion: If enterprise discovers technological change and characters of other enterprise or technology, enterprise could judge a direction of technology which will be developed in the near term and a plan which utilized existing technology to increase enterprise's profits.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.243-248
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• 2011

The 3-dimensional flow field has been investigated by numerical analysis in a 2.5MW wind turbine blade. Complicated and separated flaw phenomena in the wind turbine blade were captured by the Reynolds-averaged Navier-Stokes(RANS) steady flaw simulation using general-purpose code, CFX and the mechanism of vortex structure behavior is elucidated. The vortical flow field in a wind turbine rotor is dominated by the tip vortex and hub separation vortex. The tip vortex starts to be formed near the blade tip leading edge. As the tip vortex develops in the tangential direction, interacting with boundary layer from the blade tip trailing edge. The hub separation vortex is generated near the blade hub leading edge and develops nearly in the span-wise direction. Furthermore, 3-dimensional blade tip shape has been designed for increasing shrift power and reducing thrust force on the wind turbine blade. It is expected that the behavior of the tip vortex and hub separation vortex plays a major role in aerodynamic and aeroacoustic characteristics.