• Advances in nano research
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• v.4 no.4
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• pp.295-307
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• 2016

The present research work reports a low temperature ($40^{\circ}C$) chemical precipitation technique for synthesizing hydroxyapatite (HAp) nanoparticles of spherical morphology through a simple reaction of calcium nitrate tetrahydrate and di-ammonium hydrogen phosphate at pH 11. The crystallinity of the single-phase nanoparticles could be improved by calcinating at $600^{\circ}C$ in air. Thermogravimetric and differential thermal analysis (TG-DTA) revealed the synthesized HAp is stable up to $1200^{\circ}C$. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) studies confirmed the formation of spherical nanoparticles with average size of $23.15{\pm}2.56nm$ and Ca/P ratio of 1.70. Brunauer-Emmett-Teller (BET) isotherm of the nanoparticles revealed their porous structure with average pore size of about 24.47 nm and average surface area of $78.4m2g^{-1}$. Fourier transform infrared spectroscopy (FTIR) was used to confirm the formation of P-O, OH, C-O chemical bonds. Cytotoxicity and MTT assay on MG63 osteogenic cell lines revealed nontoxic bioactive nature of the synthesized HAp nanoparticles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.419-422
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• 2000

This paper was to measure the structure, piezoelectric properties of 0.05Pb($A1_{0.5}$$Nb_{0.5}$)-0.95Pb($Zr_{0.52}$$Ti_{0.48}$)$O_3$ ceramics dopped with additive after creating the specimens with a general method. It is shown that X-ray diffraction pattern variation of lines (200) have tendency to move in simple peak by addition of additive. According to the increase of $Cr_2$$O_3$, tetragonality hardly have variation, according to the increase of $Fe_2$$O_3$, tetragonality decreased on the whole. According to dopping with $Cr_2$$O_3$ and $Fe_2$$O_3$, electromechanical factor(kp) largely increased, in case of sintering at $1200^{\circ}C$ kp was maximum value of 40.04[%] at $Cr_2$$O_3$ 0.3wt%, and maximum value of kp 42.9 [%] at $Fe_2$$O_3$, 0.9wt%. In case of sintering at 120$0^{\circ}C$, mechanical duality factor(Qm) was maximum value of Qm 268.8 at $Cr_2$$O_3$, 0.9 wt%.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.4
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• pp.165-172
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• 2006

In this paper we present a technique for detecting cross-reference points that allows improving watermark detect-ability. In general, Harris detector is commonly used for finding salient points. Harris detector is a kind of combined corner and edge detector which is based on neighboring image data distribution, therefore it has some limitation to find accurate salient points after watermark embedding or any kinds of digital attacks. The new method proposed in this paper used not data distribution but geometrical structure of a normalized image in order to avoid pointing error caused by the distortion of image data. After normalization, we constructed pre-specified number of virtual lines from top to bottom and left to right, and several of cross points were selected by a random key. These selected points specify almost same positions with the accuracy more than that of Harris detector after digital attacks. These points were arranged by a random key, and blocks centered in these points were formed. A reference watermark is formed by a block and embedded in the next block. Because same alteration is applied to the watermark generated and embedded blocks. the detect-ability of watermark is improved even after digital attacks.

• THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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• v.5 no.1
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• pp.103-118
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• 1999

The activity of N-acetylglucosamitnyltransferase(GnT) III and V on a Melanoma B-16 was examined after incubation with interleukin 1 (IL-1). While augumenting cell proliferation, IL-1 resulted in a decrease of GnT-III activity and an increase of GnT-V activities. Consistant with this, Melanoma B-16 cultured with IL-1 showed increased affinlity to Daturam stramonium lectin, which recognizes asialo-tri- and asialeo-tetra-antenery N-linked oligosaccharides. These results indicate that IL-1 modulate glycosyltransferase activity and the oligosaccharide structure of target cells. On the other hand, to investigate whether or not TKM-SG affect GnT-V gene expression in lung metastatic carcinoma, we used RT-PCR methods. TKM-SG treated cell lines showed low levels of secretion of GnT-V mRNA transcription as elucidated by RT-PCR. Thus, with together lower GnT-V activity levels in the medium, TKM-SG was highly effective for lung cancer metastasis treatment and it was concluded that the medicine can be used as a potent anti-lung cancer metastasis medicine.

• Journal of Plant Biotechnology
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• v.46 no.2
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• pp.79-87
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• 2019

One of wild diploid Solanum species, Solanum chacoense, is one of the excellent resources for potato breeding because it is resistant to several important pathogens, but the species is not sexually compatible with potato (S. tuberosum) causing the limitation of sexual hybridization between S. tuberosum and S. chacoense. Therefore, diverse traits regarding resistance from the species can be introgressed into potato via somatic hybridization. After cell fusion, the identification of fusion products is crucial with molecular markers. In this study, S. chacoense specific markers were developed by comparing the chloroplast genome (cpDNA) sequence of S. chacoense obtained by NGS (next-generation sequencing) technology with those of five other Solanum species. A full length of the cpDNA sequence is 155,532 bp and its structure is similar to other Solanum species. Phylogenetic analysis resulted that S. chacoense is most closely located with S. commersonii. Sequence alignment with cpDNA sequences of six other Solanum species identified two InDels and 37 SNPs specific sequences in S. chacoense. Based on these InDels and SNPs regions, four markers for distingushing S. chacoense from other Solanum species were developed. These results obtained in this research could help breeders select breeding lines and facilitate breeding using S. chacoense in potato breeding.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1111-1116
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• 2009

For expression of contour lines in mobile GIS environments, the client needs to receive the numerical data with the topographical map from a server. At this point, a client can't get the entire raw data because of the mobile characteristics. The approach to get representative points and to make isogram by interpolation methods, has some problems. The approach requires huge computing overhead at the client and doesn't guarantee the correctness of the isogram. In this paper, a data structure, algorithm and implementation results for efficient transmission of contour information to a client which is constructed from elevation information at a server, are proposed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1248-1253
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• 2008

The MCS(Micro-Coplanar Strip) line with ground has been analyzed. The conformal mapping method is used to calculate the quasi-static effective dielectric constant and characteristic impedance of this MCS line. The computed results of the present work are found to be in good agreement when compared with the results obtained using commercial S/W, IE3D. And in this paper, the stepped-impedance low pass filter is designed and fabricated with MCS lines for improving the frequency responses. The LPF proposed structure has been also designed and implemented to have the sharp attenuation characteristics in stop band. The agreement between simulation and measurement results verify the implemented LPF.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.955-962
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• 2005

Power efficiency, lifetime and stable manufacturing processes are the crucial parameters for the success of organic light emitting diodes (OLEDs) in display and lighting applications. Highest power efficiencies of PIN-OLEDs for all principal colours and for bottom and top emission OLED structures have been demonstrated. The PIN structure, which means the incorporation of intentionally doped charge carrier transport layer in a suitable OLED layer setup, lowers the operating voltage to achieve highest power efficiencies. Up to now the n-doping of the electron transport layer has been done by alkali metal co-deposition. This has main draw-backs in terms of manufacturability, since the handling of large amounts of pure Cs is a basic issue in production lines. Here we present in detail results on PIN-OLEDs comprising a newly developed molecular n-dopant. All the previous OLED performance data based on PIN-OLEDs with alkali metal doping could be reproduced and will be further improved in the future. Hence, for the first time, a full manufacturing compatible PIN-OLED is available.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.644-647
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• 2001

Amorphous As-Ge-Se-S thin films have been studied with the aim of identifying optimum etching condition which can be used to produce holographic grating structure for use as diffractive optical elements. In this study, holographic gratings have been formed using He-Ne laser(632.8nm), and fabricated by the method of wet etching using NaOH etchant with various concentration(0.26N, 0.33N, 0.40N). The diffraction efficiency was obtained by +1st order intensity of the diffracted beam. The formed grating profiles were observed by atomic force microscope and showed that the expected grating profile could be achieved by controlling the etching time. Over-etching resulted in under-cutting of the grating lines. The highest 1st order diffraction efficiency for these gratings was about 5.05%.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.41-44
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• 2003

We propose portable equipment that monitors current and voltage of high-potential power transmission lines. In the equipment, a current and voltage sensor are attached to an insulator that supports a power transmission line: A clamped to the power line and the detected current signal is transmitted to the ground station by a wireless optical link using transmission line is detected by a high resistance element, zinc oxide (ZnO). That acts as a potential divider between the power line and ground. We make an experimental device for 66kV power line and demonstrate that it can monitor currents proposed equipment is small-sized, light, and inexpensive in comparison with the conventional CT (current transformer) and PT (potential transformer) since it does not require high potential insulators and magnetic cores, further, the equipment is easily installed owing to its small size and its simple structure.