• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.896-897
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• 2006

In the viewpoint of engineering, materials problem is a key problem, which determines whether the exploitation of fusion energy will be success. The most important class of fusion materials is plasma-facing materials (PFM). W, as high Z high melting-point metal is one of the most important candidate materials due to its high plasma erosion resistance. Improving the ductility of W and W based alloy, lowering its ductile-brittleness transition temperature for meeting the requirements of fusion application is an important task. In this paper, severalpowder meatllurgy methods of fabricating W and W based materials are being investigated.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.43.2-43.2
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• 2016

We present results of a calibrator search near twenty evolved stars using the Korean VLBI Network (KVN). Our evolved star targets include candidate sources for a Key Science Project (KSP) of the KVN. The KSP plans to investigate the spatial structure and dynamical effects between SiO and H2O maser regions including mass-loss process and development of asymmetry in circumstellar envelopes of evolved stars. For these purposes, we need compact and strong extragalactic sources close to the evolved stars. We carried out 5 observations in order to detect radio continuum sources that can be used for source frequency phase-referencing (SFPR) -based analysis. We observed 153 sources, out of which we detected 29 at 22 GHz and 20 at 43 GHz at signal-to-noise ratios higher than 50 at all baselines. Therefore, we successfully found target and calibrator pairs for the KVN KSP.

• ETRI Journal
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• v.40 no.1
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• pp.89-100
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• 2018

Millimeter wave communication is one of the main disruptive technologies in upcoming 5G mobile networks. One of the first candidate applications, which will be commercially ready by 2020, is wireless backhaul links or wireless last mile communication. This paper provides an analysis of this use-case from radio engineering and implementation perspectives. Furthermore, preliminary experimental results are shown for a proof-of-concept wireless backhaul solution developed within the EU-KR 5GCHAMPION project, which will be showcased during the 2018 Winter Olympic Games in Korea. In this paper, we verify system level calculations and a theoretical link budget analysis with conductive and radiated over-the-air measurements. The results indicate that the implemented radio solution is able to achieve the target key performance indicator, namely, a 2.5 Gbps data rate on average, over a range of up to 200 m.

• Korean Journal of Biological Psychiatry
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• v.3 no.1
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• pp.14-21
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• 1996

Molecular genetic approaches contribute to the understanding of the underlying genetic mechanism for schizophrenia. Currently genetic evidence rests on molecular genetic methods. However, the result are contradictory and somewhat confusing due to genetic heterogeneity, incomplete penetrance, misspecification of genetic model. It is expected that molecular genetics could provide key answers to the genetic cause of schizophrenia. The purpose of this article is to call attention of the readers to heterogeneity, linkage, association, basic molecular genetic methods and genetic markers and to the need far further research. It is the author's hope thai continuous research on the molecular genetics con provide clinicians with better understanding of the schizophrenia.

• YAKHAK HOEJI
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• v.47 no.2
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• pp.104-109
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• 2003

The present paper reviews the notion and comparison of the Korea Food and Drug Administration(KFDA) general pharmacology and the International Conference on Harmonisation (ICH) safety pharmacology. General pharmacology or safety pharmacology is termed the study to determine the potential of a compound to induce adverse pharmacological effects. KFDA general pharmacology studies have been considered an important component in drug safety assessment and these were originally referred to those designed to examine effects other than the primary therapeutics effect of a drug candidate. The KFDA notified the Guideline for General Pharmacology in 1997. Safety pharmacology studies were focused on identifying adverse effects on physiological functions. In the ICH came into place S7A Safety Pharmacology Studies for Human Pharmaceuticals in 2001. A new chemical entity should be assessed for its side effects, initially in those physiological systems which are generally agreed to be the key systems that are essential for life; these "core system" include the central nervous system, cardiovascular system and respiratory system in safety pharmacology studies. These studies should be performed in compliance with Good Laboratory Practice (GLP).

• Korean Journal of Materials Research
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• v.25 no.10
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• pp.537-542
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• 2015

One-dimensional (1D) silver nanostructures, which possess the highest conductivity among all room-temperature materials, moderate flexibility and high transmittance, are one of the most promising candidate materials to replace conventional indium tin oxide transparent electrodes. However, the short length and large diameter of 1D silver nanostructures cause a substantial decrease in the optical transparency or an increase in the sheet resistance. In this work, ultra-long silver nanofiber networks were synthesized with a low-cost and scalable electrospinning process, and the diameter of the nanofibers were finetuned to achieve a higher aspect ratio. The decrease in the diameter of the nanofibers resulted in a higher optical transparency at a lower sheet resistance: 87 % at $300{\Omega}/sq$, respectively. It is expected that an electrospun silver nanofiber based transparent electrode can be used as a key component in various optoelectronic applications.

• Journal of Information Processing Systems
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• v.11 no.3
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• pp.342-353
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• 2015

It is widely accepted that single carrier frequency division multiple access (SC-FDMA) is an excellent candidate for broadband wireless systems. Channel estimation is one of the key challenges in SC-FDMA, since accurate channel estimation can significantly improve equalization at the receiver and, consequently, enhance the communication performances. In this paper, we study the application of compressive sensing for sparse channel estimation in a SC-FDMA system. By skillfully designing pilots, their patterns, and taking advantages of the sparsity of the channel impulse response, the proposed system realizes channel estimation at a low cost. Simulation results show that it can achieve significantly improved performance in a frequency selective fading sparse channel with fewer pilots.

• Journal of Information Technology Services
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• v.7 no.4
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• pp.87-99
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• 2008

As the technologies for telecommunication have been evolving, more enhanced information services and integrated information systems have been introduced, which can manage a variety of information from the heterogeneous systems. The major obstacle for the integrated information systems is the integrating heterogeneous databases in the systems and the heterogeneity problems can be classified into the structural and data heterogeneities. However, the previous researches have mainly highlighted into the solving structural heterogeneity problems. This paper identifies the data heterogeneity problems for multi-database schema integrations and proposes a new solving method. We analyze the semantics equivalence in data values based on the functional dependency, primary and candidate keys, and present a procedural solution of data heterogeneity in the perspective of the concept of attribute equivalence, integration key and conceptual integration table.

• Nuclear Engineering and Technology
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• v.40 no.4
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• pp.251-254
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• 2008

Issues and themes concerned with nuclear power plant uprating are examined. Attention is brought to the fact that many candidate nuclear power plants for uprating have anyway been operated below their rated power for a significant part of their operating life. The key issues remain safety and reliability in operation at all times, irrespective of the nuclear power plant's chronological or design age or power rating. The effects of power uprates are discussed in terms of material aspects and expected demands on the systems, structures and components. The impact on operation and maintenance methods is indicated in terms of changes to the ageing surveillance programmes. Attention is brought to the necessity checking or revising operator actions after power up-rating has been implemented.

• Journal of Microbiology and Biotechnology
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• v.31 no.10
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• pp.1350-1357
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• 2021

Staphylococcus aureus (S. aureus) is a major pathogen that causes human pneumonia, leading to significant morbidity and mortality. S. aureus coagulase (Coa) triggers the polymerization of fibrin by activating host prothrombin, which then converts fibrinogen to fibrin and contributes to S. aureus pathogenesis and persistent infection. In our research, we demonstrate that isovitexin, an active traditional Chinese medicine component, can inhibit the coagulase activity of Coa but does not interfere with the growth of S. aureus. Furthermore, we show through thermal shift and fluorescence quenching assays that isovitexin directly binds to Coa. Dynamic simulation and structure-activity relationship analyses suggest that V191 and P268 are key amino acid residues responsible for the binding of isovitexin to Coa. Taken together, these data indicate that isovitexin is a direct Coa inhibitor and a promising candidate for drug development against S. aureus infection.