• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
• /
• pp.239-242
• /
• 2009

Since the atmospheric clearness index is main factor for evaluating atmosphere environment, it is necessary to estimate its characteristics all over the major cities in Korea. We have begun collecting clearness index data since 1982 at 16 different cities and considerable effort has been made for constructing a standard value from measured data at each city. The new clearness data will be extensively used by evaluating atmospheric environment analysts as well as by solar application designers or users. From the results, yearly mean 63.6 % of the atmospheric clearness index was evaluated for clear day all over in Korea

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2001년도 춘계학술대회 논문집
• /
• pp.120-123
• /
• 2001

The semi-solid casting will have a higher internal integrity, mechanical properties and dimensional accuracy than the conventional castings. This process can reduce the manufacturing costs and finished weight for critical components. The semi-solid casting are capable of greater dimensional repeatbility, this supplies considerable savings when extensive machining, salvage and scrap are key variables in the current automotive product. One of the most important factor regarding the semi-solid die casting process are the reheating method of the raw materials to the semi-solid state. Therefore, in this present work, the horizontal type induction heating system to obtain the optimal reheating conditions suitable for semi-solid die casting process was designed and manufactured. And the microstructure of reheated materials was investigated.

• Toxicological Research
• /
• 제17권
• /
• pp.89-96
• /
• 2001

Recently, considerable attention has been focused on the role of cyclooxygenase-2 (COX-2) in the carcinogenesis as well as in inflammation. Improperly overexpressed COX-2 has been observed in many types of human cancers and transformed cells in culture. Thus, it is conceivable that targeted inhibition of abnormally or improperly up-regulated COX-2 provides one of the most effective and promising strategies for cancer prevention. A ubiquitous eukaryotic transcription factor, NF-kB is considered to be involved in regulation of COX-2 expression. Furthermore, extracellular-regulated protein kinase and p38 mitogen-activated protein (MAP) kinase appear to be key elements of the intracellular signaling cascades involved in NF-kB activation in response to a wide array of external stimuli. Certain chemopreventive phytochemicals suppress activation of NF-kB by blocking one or more of the MAP kinases, which may contribute to their inhibitory effects on COX-2 induction. One of the plausible mechanisms by which chemopreventive phytochemicals inhibit NF-kB activation involves suppression of degradation of the inhibitory unit I kB, which hampers subsequent translocation of p65, the functionally active subunit of NF-kB.

• 한국동물번식학회:학술대회논문집
• /
• 한국동물번식학회 2002년도 춘계학술발표대회 발표논문초록집
• /
• pp.17-17
• /
• 2002

There are considerable reports that the expression of insulin-like growth factor-Ⅰ (IGF-Ⅰ) is related to ovarian regulation and oviductal development in poultry. Korean Native Ogol Chicken (KNOC) have been inbred to keep a pure line so that there has been limitation in the improvement of egg productivity by genetic studies. Therefore, this study was conducted to investigate the early egg productivity of KNOC pre-selected by IGF-Ⅰ expression. (omitted)

• Computers and Concrete
• /
• 제14권2호
• /
• pp.163-174
• /
• 2014

Damping as a material property plays an important role in decreasing dynamic response of structures. However, very little is known about the evaluation and application of the actual damping of Fiber Reinforced Polymer Confined Reinforced Concrete (FRP-C RC) material which is widely adopted in civil engineering at present. This paper first proposes a stress-dependent damping model for FRP-C RC material using a validated Finite Element Model (FEM), then based on this damping-stress relation, an iterative scheme is developed for the computations of the non-linear damping and dynamic response of FRP-C RC columns at any given harmonic exciting frequency. Numerical results show that at resonance, a considerable increase of the loss factor of the FRP-C RC columns effectively reduces the dynamic response of the columns, and the columns with lower concrete strength, FRP volume ratio and axial compression ratio or higher longitudinal reinforcement ratio have stronger damping values, and can relatively reduce the resonant response.

• 제어로봇시스템학회논문지
• /
• 제13권4호
• /
• pp.315-319
• /
• 2007

A technique to model plasma processes was presented. This was accomplished by combining the backpropagation neural network (BPNN) and genetic algorithm (GA). Particularly, the GA was used to optimize five training factor effects by balancing the training and test errors. The technique was evaluated with the plasma etch data, characterized by a face-centered Box Wilson experiment. The etch outputs modeled include Al etch rate, AI selectivity, DC bias, and silica profile angle. Scanning electron microscope was used to quantify the etch outputs. For comparison, the etch outputs were modeled in a conventional fashion. GABPNN models demonstrated a considerable improvement of more than 25% for all etch outputs only but he DC bias. About 40% improvements were even achieved for the profile angle and AI etch rate. The improvements demonstrate that the presented technique is effective to improving BPNN prediction performance.

• 대한치과의사협회지
• /
• 제48권2호
• /
• pp.113-118
• /
• 2010

Titanium and titanium alloys are the most common materials used for dental and biomedical implants, owing to their biocompatibility and favourable mechanical properties. However infection of the region surrounding a dental implant by pathogenic microorganisms is a significant factor in implant failure. Prevention and control of microbial colonization of implant surfaces is considerable interest to the biomedical community. One important strategy is to render the implant surface antibacterial by impeding the formation of biofilm. A number of approaches have been proposed for this purpose. Therefore, we reviewed the researches of antibacterial coatings on titanium implants in this articles.

• 대한전기학회논문지:전력기술부문A
• /
• 제55권2호
• /
• pp.76-84
• /
• 2006

Interstate electric power system, as an alternative for energy cooperation under regional economic block, has been hotly debated before progressing the restructure in electric power industry and rapidly expanded in many regions after 1990s. Especially, since northeast asia has strong supplementation in resource, load shape, fuel mix etc., interconnection of electric power systems in this region may bring considerable economic benefits. This paper implements a mathematical optimization model, ORIRES, proposed by Russia, in analysing the economic feasibility of system interconnection. Additional analyses on the environmental impact of the system interconnection, and sensitivity of key factor inputs have been performed.

• BMB Reports
• /
• 제48권11호
• /
• pp.599-608
• /
• 2015

Regeneration, a process of reconstitution of the entire tissue, occurs throughout life in the olfactory epithelium (OE). Regeneration of OE consists of several stages: proliferation of progenitors, cell fate determination between neuronal and non-neuronal lineages, their differentiation and maturation. How the differentiated cell types that comprise the OE are regenerated, is one of the central questions in olfactory developmental neurobiology. The past decade has witnessed considerable progress regarding the regulation of transcription factors (TFs) involved in the remarkable regenerative potential of OE. Here, we review current state of knowledge of the transcriptional regulatory networks that are powerful modulators of the acquisition and maintenance of developmental stages during regeneration in the OE. Advance in our understanding of regeneration will not only shed light on the basic principles of adult plasticity of cell identity, but may also lead to new approaches for using stem cells and reprogramming after injury or degenerative neurological diseases.

• 비파괴검사학회지
• /
• 제26권3호
• /
• pp.198-205
• /
• 2006

The necessity of nondestructively inspecting austenitic steels, fiber-reinforced composites, and other inherently anisotropic materials has stimulated considerable interest in developing beam models for anisotropic media. The properties of slowness surface playa key role in the beam models based on the paraxial approximation. In this paper, we apply a modular multi-Gaussian beam (MMGB) model to study the effects of material anisotropy on ultrasonic beam profile. It is shown that the anisotropic effects of beam skew and excess beam divergence enter into the MMGB model through parameters defining the slope and curvature of the slowness surface. The overall beam profile is found when the quasilongitudinal(qL) beam propagates in the symmetry plane of transversely isotropic austenitic steels. Simulation results are presented to illustrate the effects of these parameters on ultrasonic beam diffraction and beam skew. The MMGB calculations are also checked by comparing the anisotropy factor and beam skew angle with other analytical solutions.