• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.5
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• pp.217-222
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• 2007

Microwave dielectric properties of $(1-x)CaWO_4-xYNbO_4$ ceramics have been investigated as a function of $YNbO_4$ content($0.05{\leq}x{\leq}0.4$). A single phase with tetragonal scheelite structure was obtained up to x=0.10 and then the secondary phase with fergusonite structure was increased. With the increase of $YNbO_4$ content, apparent densities of the specimens were decreased. This results were due to the lower theoretical density of $YNbO_4(5.581g/cm^3)$ than that of $CaWO_4(6.117g/cm^3)$. Dielectric constant(K) and quality factor(Qf) were decreased with $YNbO_4$ content which could be attribute to the decrease of density and the increase of secondary phase. Temperature coefficient of resonant frequency (TCF) of the specimens with the $YNbO_4$ content was depended on dielectric mixing rule.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.382.2-382.2
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• 2014

We explain a method to fabricate multi-layered transparent conductive films (TCF) using graphene oxide (GO), copper powder and polyurethane (PU) solution. The flexible graphene nanosheets (GNSs) serve as nanoscale connection between conductive copper nanoparticles (CuNps) and PU nanofibers, resulting in a highly flexible TCF. To fabricate conductive films with high transmittance, polyurethane (PU) nanofibers were used for a conductive network consisting of CuNps and GNSs (CuNps-GNSs). In this experiment, copper powder and graphene oxides were mixed in deionized water with the ultrasonication for 2 h. NaBH4 solution is used as a reduction agents of CuNps and GNSs (CuNps-GNSs) under a nitrogen atmosphere in the oil bath at 100% for 24 h to mixed. The purified and dispersed CuNp-GNS were obtained in deionized water, and diluted to a 10wt.% based on the contents of GNSs. Polyurethane (PU) nanofibers on a PET substrate were formed by electrospinning method. PET slides coated with the PU nanofibers were immersed into CuNp-GNS solution for several second, rinsed briefly in deionized water, and dried to obtain self-assembled CuNp-GNS/PU films. The morphology of the multi-layered films were characterized with a field emission scanning electron microscope (FE-SEM, Hitachi S-4700) and atomic force microscope (AFM, PSIA XE-100). The electrical property was analysed by the I-V measurement system and the optical property was measured by the UV/VIS spectroscopy.

• Journal of Digestive Cancer Research
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• v.4 no.2
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• pp.64-76
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• 2016

The step-wise process of colorectal carcinogenesis from aberrant crypt foci, adenoma to adenocarcinoma, is relatively suitable for chemopreventive intervention. Accumulated evidences have revealed that maintaining an undifferentiated state (stemness), inflammation, and oxidative stress play important roles in this colon carcinogenesis process. However, appropriate molecular targets that are applicable to chemopreventive intervention regarding those three factors are still unclear. In this review, we summarized appropriate molecular targets by identification and validation of the prospective targets from a comprehensive overview of data that showed colon cancer preventive effects in clinical trials, epidemiological studies and basic research. We first selected a study that used aspirin, statins and metformin from FDA approved drugs, and epigallocatechin-gallate and curcumin from natural compounds as potential chemopreventive agents against colon cancer because these agents are considered to be promising chemopreventive agents. Experimental and observational data revealed that there are common target molecules in these potential chemopreventive agents: T-cell factor/lymphoid enhancer factor (TCF/LEF), nuclear factor-&B (NF-κB) and nuclear factor-erythroid 2-related factor 2(NRF2). Moreover, these targets, TCF/LEF, NF-κB and NRF2, have been also indicated to suppress maintenance of the undifferentiated state, inflammation and oxidative stress, respectively. In the near future, novel promising candidate agents for colon cancer chemoprevention could be identified by integral evaluation of their effects on these three transcriptional activities.

• Molecules and Cells
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• v.41 no.9
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• pp.830-841
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• 2018

Recent studies have indicated that microRNAs (miRNAs) play an important role in hepatocellular carcinoma (HCC) progression. In this study, we showed that miR-766-3p was decreased in approximately 72% of HCC tissues and cell lines, and its low expression level was significantly correlated with tumour size, TNM stage, metastasis, and poor prognosis in HCC. Ectopic miR-766-3p expression inhibited HCC cell proliferation, colony formation, migration and invasion. In addition, we showed that miR-766-3p repressed Wnt3a expression. A luciferase reporter assay revealed that Wnt3a was a direct target of miR-766-3p, and an inverse correlation between miR-766-3p and Wnt3a expression was observed. Moreover, Wnt3a up-regulation reversed the effects of miR766-3p on HCC progression. In addition, our study showed that miR-766-3p up-regulation decreased the nuclear ${\beta}-catenin$ level and expression of Wnt targets (TCF1 and Survivin) and reduced the level of MAP protein regulator of cytokinesis 1 (PRC1). However, these effects of miR-766-3p were reversed by Wnt3a up-regulation. In addition, PRC1 upregulation increased the nuclear ${\beta}-catenin$ level and protein expression of TCF1 and Survivin. iCRT3, which disrupts the ${\beta}-catenin-TCF4$ interaction, repressed the TCF1, Survivin and PRC1 protein levels. Taken together, our results suggest that miR-766-3p down-regulation promotes HCC cell progression, probably by targeting the Wnt3a/PRC1 pathway, and miR-766-3p may serve as a potential therapeutic target in HCC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.130-130
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• 2009

This paper describes the temperature characteristics of polycrystalline 3C-SiC micro resonators. The 1.2 ${\mu}m$ and 0.4 ${\mu}m$ thick polycrystalline 3C-SiC cantilever and doubly clamped beam resonators with 60 ~ 100 ${\mu}m$ lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonance was measured by a laser vibrometer in vacuum at temperature range of $25{\sim}200^{\circ}C$. The TCF(Temperature Coefficient of Frequency) of 60, 80 and 100 ${\mu}m$ long cantilever resonators were -9.79, -7.72 and -8.0 $ppm/^{\circ}C$. On the other hand, TCF of 60, 80 and 100 ${\mu}m$ long doubly clamped beam resonators were -15.74, -12.55 and -8.35 $ppm/^{\circ}C$. Therefore, polycrystalline 3C-SiC resonators are suitable with RF MEMS devices and bio/chemical sensor applications in harsh environments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.781-785
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• 2016

With trend of the miniaturization and the high-functionalizing of mobile communication system, low-loss microwave dielectric materials are widely used for high frequency communication components. These dielectric materials should be co-sintered with highly electric-conducting metal such as silver or copper for high-frequency and thick film process application. Sintering temperature of $Ca(Li_{1/3}Nd_{2/3})_{0.2}Ti_{0.8}]O_{3-{\delta}}$, which has excellent dielectric properties such as ${\varepsilon}_r$ above 40, quality factor ($Q{\cdot}f_0$) above 16,000 GHz, and TCF (temperature coefficient of resonant frequency) of $-20{\sim}-10ppm/^{\circ}C$, is reported as high as $1,175^{\circ}C$, so it could not be co-sintered with silver or copper. Therefore in this study, low-temperature melting glasses of Zn-B-O and Zn-B-Si-O systems were added to $Ca[(Li_{1/3}Nb_{2/3})_{0.8}Ti_{0.2}]O_{3-{\delta}}$ to lower its sintering temperature under $900^{\circ}C$ without losing excellency of dielectric properties. With 15 weight % of Zn-B-Si-O glass and sintered at $875^{\circ}C$, specimen showed density of $4.11g/cm^3$, ${\varepsilon}_r$ of 40.1, $Q{\cdot}f_0$ of 4,869 GHz, and TCF of $-5.9ppm/^{\circ}C$. With 15 weight % of Zn-B-O glass and sintered at $875^{\circ}C$, specimen showed density of $4.14g/cm^3$, ${\varepsilon}_r$ of 40.4, $Q{\cdot}f_0$ of 7,059 GHz, and TCF of $-0.92ppm/^{\circ}C$.

• Animal Bioscience
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• v.36 no.2
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• pp.191-199
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• 2023

Objective: This study aimed to investigate the significant single nucleotide polymorphisms (SNPs) and genes associated with nine reproduction and morphological traits in three breed populations of Chinese goats. Methods: The genome-wide association of nine reproduction and morphological traits (litter size, nipple number, wattle, skin color, coat color, black dorsal line, beard, beard length, and hind leg hair) were analyzed in three Chinese native goat breeds (n = 336) using an Illumina Goat SNP50 Beadchip. Results: A total of 17 genome-wide or chromosome-wide significant SNPs associated with one reproduction trait (litter size) and six morphological traits (wattle, coat color, black dorsal line, beard, beard length, and hind leg hair) were identified in three Chinese native goat breeds, and the candidate genes were annotated. The significant SNPs and corresponding putative candidate genes for each trait are as follows: two SNPs located on chromosomes 6 (CSN3) and 24 (TCF4) for litter size trait; two SNPs located on chromosome 9 (KATNA1) and 1 (UBASH3A) for wattle trait; three SNPs located on chromosome 26 (SORCS3), 24 (DYM), and 20 (PDE4D) for coat color trait; two SNPs located on chromosome 18 (TCF25) and 15 (CLMP) for black dorsal line trait; four SNPs located on chromosome 8, 2 (PAX3), 5 (PIK3C2G), and 28 (PLA2G12B and OIT3) for beard trait; one SNP located on chromosome 18 (KCNG4) for beard length trait; three SNPs located on chromosome 17 (GLRB and GRIA2), 28 (PGBD5), and 4 for hind leg hair trait. In contrast, there were no SNPs identified for nipple number and skin color. Conclusion: The significant SNPs or genes identified in this study provided novel insights into the genetic mechanism underlying important reproduction and morphological traits of three local goat breeds in Southern China as well as further potential applications for breeding goats.

• Korean Journal of Materials Research
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• v.11 no.8
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• pp.708-712
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• 2001

Microwave dielectric properties of $(Pb_{0.2}Ca_{0.8})[(Ca_{1/3}Nb{2/3})_{1-x}Ti_x]O_3$ ceramics were investigated as a function of $Ti^{4+}$ content (0.05$\leq$x$\leq$0.35). A single perovskite phase was obtained from x=0.05 to x=0.15, and $TiO_2$ and $CaNb_2O^6$ were detected as a secondary phase beyond x=0.2. The structure was changed from orthorhombic at x=0.05 to cubic at x=0.35. Dielectric constant(K) was increased with increase of $Ti^{4+}$ content due to increase of rattling effect, and was inversely proportional to the cube of the average radius of B-site cation, however, Qf value was decreased, which was due to the decrease of grain size and the secondary phase. With the increase of $Ti^{4+}$ content, the temperature coefficient of resonant frequency(TCF) was controlled from -27.36 ppm/$^{\circ}C$ value to +18.4 ppm/$^{\circ}C$ value, which was caused by the influence of tolerance factor(t) and the bond valence of B-site. Typically, K of 51.67, Qf of 7268(GHz), TCF of 0 ppm/$^{\circ}C$ were obtained in the $(Pb_{0.2}Ca_{0.8})[(Ca_{1/3}Nb_{2/3})_{0.8}Ti_0.2]O_3$ sintered at 13$50^{\circ}C$ for 3h.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.988-996
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• 1998

BN ceramics with 0.07wt% $V_{2}O_{5}$ and 0.03wt% CuO(BNC3V7) sintered at $900^{\circ}C$ where it is possible for these to be co-fired with Ag electrode. Dielectricconstant of 44.3, TCF of 22 ppm$/^{\circ}C$ and $Qxf_{o}$ value of 22,000 GHz can be obtained from BNC3V7, multilayer type band pass filters using tapped method and conventional method were designed for PCS (Personal Communication System) applications. Tapped method by adopting input/output-tapping scheme the chip filter stucture becomes simpler and needs fewer layers than that using the conventional input/output-coupling scheme. A multilayer type band pass filter fabricated by screen-printing with silver electrode after tape casting. The simulated characteristics of the fabricated filters sintered at $900^{\circ}C$ were compared with the designed ones. Even though the centered frequencies of tapped and conventional band pass chaip filters were measured to shift about 90MHz downward, the band pass characteristics of both filters were similar that of designed ones. The spuriousresonance characteristic of tapped pass chip filter was better than that of conventional chip filer.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.595-597
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• 2002

MPEG그룹은 미디어 객체를 시간과 3차원 공간상에 배치하여, 멀티미디어 컨텐츠를 표현하고, 사용자의 상호작용을 가능하게 하는 MFEG-4 System물 표준화하였으며, 다양한 전송계층 (File, TCF/IP, Broadcasting등)을 통합하여 처리할 수 있는 MPEG-4 System의 Multimedia Interface Framework)[3] 전송규약을 표준화하였다. 이 논문에서는 MPEG-4 System을 이용하여 비디오, 오디오, 그랙픽과 같은 다양한 미디어들을 결합하해주고 사용자와의 상호작용에 의한 실시간 표현을 가능하게 해주며 사용자가 MPEG-4 Sytem에 대해서 잘 알고 있지 않더라도 손쉽게 MPEG-4미디어 파일을 만들 수 있도록 해주는 저작툴을 제안한다 [1,3,5]